Raspberry Pi Zeroで動作中にインターネットに接続できなくなる

CANDY Pi Lite LTE M を購入してラズパイZeroに載せてセットアップを行いました。
しばらく連続運用しているとインターネットに接続できなくなります。
OSはRasbian busterです。WiFiルーター化しておりWiFiで接続して以下のログ等を取りました。
その時CANDY Pi のLEDは二つとも点滅していました。



syslogは以下です。
Sep 25 14:55:14 **** pppd[746]: No response to 4 echo-requests
Sep 25 14:55:14 **** pppd[746]: Serial link appears to be disconnected.
Sep 25 14:55:14 **** pppd[746]: Connect time 2826.1 minutes.
Sep 25 14:55:14 **** pppd[746]: Sent 19987966 bytes, received 269707881 bytes.
Sep 25 14:55:15 **** dnsmasq[481]: reading /run/dnsmasq/resolv.conf
Sep 25 14:55:15 **** dnsmasq[481]: ignoring nameserver 192.168.22.1 - local interface
Sep 25 14:55:20 **** pppd[746]: Connection terminated.
Sep 25 15:00:01 **** CRON[12206]: (root) CMD ([12213] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:00:18 **** CRON[12206]: (CRON) info (No MTA installed, discarding output)
Sep 25 15:00:18 **** CRON[12206]: (root) END ([12213] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:10:01 **** CRON[18812]: (root) CMD ([18817] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:10:18 **** CRON[18812]: (CRON) info (No MTA installed, discarding output)
Sep 25 15:10:18 **** CRON[18812]: (root) END ([18817] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:17:01 **** CRON[23459]: (root) CMD ([23463] cd / && run-parts --report /etc/cron.hourly)
Sep 25 15:17:01 **** CRON[23459]: (root) END ([23463] cd / && run-parts --report /etc/cron.hourly)
Sep 25 15:20:01 **** CRON[25458]: (root) CMD ([25463] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:20:18 **** CRON[25458]: (CRON) info (No MTA installed, discarding output)
Sep 25 15:20:18 **** CRON[25458]: (root) END ([25463] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:30:01 **** CRON[32077]: (root) CMD ([32082] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:30:18 **** CRON[32077]: (CRON) info (No MTA installed, discarding output)
Sep 25 15:30:18 **** CRON[32077]: (root) END ([32082] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:40:01 **** CRON[6281]: (root) CMD ([6286] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:40:17 **** CRON[6281]: (CRON) info (No MTA installed, discarding output)
Sep 25 15:40:17 **** CRON[6281]: (root) END ([6286] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:48:20 **** rngd[315]: stats: bits received from HRNG source: 1500064
Sep 25 15:48:20 **** rngd[315]: stats: bits sent to kernel pool: 1443072
Sep 25 15:48:20 **** rngd[315]: stats: entropy added to kernel pool: 1443072
Sep 25 15:48:20 **** rngd[315]: stats: FIPS 140-2 successes: 75
Sep 25 15:48:20 **** rngd[315]: stats: FIPS 140-2 failures: 0
Sep 25 15:48:20 **** rngd[315]: stats: FIPS 140-2(2001-10-10) Monobit: 0
Sep 25 15:48:20 **** rngd[315]: stats: FIPS 140-2(2001-10-10) Poker: 0
Sep 25 15:48:20 **** rngd[315]: stats: FIPS 140-2(2001-10-10) Runs: 0
Sep 25 15:48:20 **** rngd[315]: stats: FIPS 140-2(2001-10-10) Long run: 0
Sep 25 15:48:20 **** rngd[315]: stats: FIPS 140-2(2001-10-10) Continuous run: 0
Sep 25 15:48:20 **** rngd[315]: stats: HRNG source speed: (min=75.821; avg=522.614; max=1025.370)Kibits/s
Sep 25 15:48:20 **** rngd[315]: stats: FIPS tests speed: (min=537.281; avg=4692.651; max=9084.302)Kibits/s
Sep 25 15:48:20 **** rngd[315]: stats: Lowest ready-buffers level: 2
Sep 25 15:48:20 **** rngd[315]: stats: Entropy starvations: 0
Sep 25 15:48:20 **** rngd[315]: stats: Time spent starving for entropy: (min=0; avg=0.000; max=0)us
Sep 25 15:50:02 **** CRON[12912]: (root) CMD ([12918] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 15:50:18 **** CRON[12912]: (CRON) info (No MTA installed, discarding output)
Sep 25 15:50:18 **** CRON[12912]: (root) END ([12918] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 16:00:01 **** CRON[19532]: (root) CMD ([19541] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 16:00:18 **** CRON[19532]: (CRON) info (No MTA installed, discarding output)
Sep 25 16:00:18 **** CRON[19532]: (root) END ([19541] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 16:03:05 **** systemd[1]: Starting Cleanup of Temporary Directories…
Sep 25 16:03:05 **** systemd-tmpfiles[21558]: [/usr/lib/tmpfiles.d/vsftpd.conf:1] Line references path below legacy directory /var/run/, updating /var/run/vsftpd/empty 竊� /run/vsftpd/empty; please update the tmpfiles.d/ drop-in file accordingly.
Sep 25 16:03:06 **** systemd[1]: systemd-tmpfiles-clean.service: Succeeded.
Sep 25 16:03:06 **** systemd[1]: Started Cleanup of Temporary Directories.
Sep 25 16:10:01 **** CRON[26144]: (root) CMD ([26149] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 16:10:18 **** CRON[26144]: (CRON) info (No MTA installed, discarding output)
Sep 25 16:10:18 **** CRON[26144]: (root) END ([26149] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 16:17:01 **** CRON[30788]: (root) CMD ([30793] cd / && run-parts --report /etc/cron.hourly)
Sep 25 16:17:01 **** CRON[30788]: (root) END ([30793] cd / && run-parts --report /etc/cron.hourly)
Sep 25 16:20:01 **** CRON[314]: (root) CMD ([323] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 16:20:18 **** CRON[314]: (CRON) info (No MTA installed, discarding output)
Sep 25 16:20:18 **** CRON[314]: (root) END ([323] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)
Sep 25 16:29:48 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:29:48 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:29:48 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:29:48 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:29:48 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:29:48 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:29:48 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:29:48 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:29:48 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:29:49 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:29:49 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:29:49 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:29:49 **** avahi-daemon[280]: Withdrawing address record for 192.168.22.1 on wlan0.
Sep 25 16:29:49 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:29:49 **** avahi-daemon[280]: Interface wlan0.IPv4 no longer relevant for mDNS.
Sep 25 16:29:49 **** dhcpcd[379]: wlan0: deleting route to 192.168.22.0/24
Sep 25 16:29:49 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:29:49 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:29:49 **** dnsmasq[481]: no servers found in /run/dnsmasq/resolv.conf, will retry
Sep 25 16:29:49 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:29:49 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:29:49 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:29:49 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:29:49 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:29:49 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:29:49 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0..
Sep 25 16:29:49 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:29:49 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:29:49 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:33:54 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:33:54 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:54 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:33:54 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:33:54 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:33:54 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:33:54 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:54 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:33:54 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0.
.
Sep 25 16:33:54 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:33:55 **** dhcpcd[379]: wlan0: soliciting an IPv6 router
Sep 25 16:33:58 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:33:58 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:33:58 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:33:58 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:33:58 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:33:58 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:33:58 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:58 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:33:58 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:33:58 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:33:58 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:33:59 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:59 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:33:59 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0..
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:33:59 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:33:59 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:59 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:33:59 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:59 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:33:59 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0.
.
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:33:59 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:33:59 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:59 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:33:59 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:59 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:33:59 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0..
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:33:59 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:33:59 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:59 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:33:59 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:33:59 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:33:59 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0.
.
Sep 25 16:33:59 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:34:00 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:34:00 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:34:00 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:34:00 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:34:00 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:34:00 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0..
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: soliciting an IPv6 router
Sep 25 16:34:00 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:34:00 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:34:00 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:34:00 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:34:00 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:34:00 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:34:00 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:34:00 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:34:00 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:34:00 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:35:09 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:35:09 **** hostapd: wlan0: STA fc:77:74:23:ec:4f RADIUS: starting accounting session EAFECB8831113CB8
Sep 25 16:35:09 **** hostapd: wlan0: STA fc:77:74:23:ec:4f WPA: pairwise key handshake completed (RSN)
Sep 25 16:35:09 **** dnsmasq-dhcp[481]: DHCP packet received on wlan0 which has no address
Sep 25 16:35:09 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:35:09 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:35:09 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:09 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:35:09 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0.
.
Sep 25 16:35:09 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:35:10 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:35:10 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:10 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:35:10 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:10 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:35:10 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0..
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:35:10 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:35:10 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:10 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:35:10 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:10 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:35:10 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0.
.
Sep 25 16:35:10 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:35:11 **** dhcpcd[379]: wlan0: soliciting an IPv6 router
Sep 25 16:35:15 **** dhcpcd[379]: wlan0: using static address 192.168.22.1/24
Sep 25 16:35:15 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:35:15 **** dhcpcd[379]: wlan0: adding route to 192.168.22.0/24
Sep 25 16:35:15 **** avahi-daemon[280]: New relevant interface wlan0.IPv4 for mDNS.
Sep 25 16:35:15 **** avahi-daemon[280]: Registering new address record for 192.168.22.1 on wlan0.IPv4.
Sep 25 16:35:15 **** dhcpcd[379]: wlan0: adding default route via 192.168.22.1
Sep 25 16:35:16 **** dnsmasq[481]: reading /run/dnsmasq/resolv.conf
Sep 25 16:35:16 **** dnsmasq[481]: ignoring nameserver 192.168.22.1 - local interface
Sep 25 16:35:17 **** dhcpcd[379]: wlan0: pid 11415 deleted default route via 192.168.22.1
Sep 25 16:35:24 **** dhcpcd[379]: wlan0: no IPv6 Routers available
Sep 25 16:35:25 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:35:25 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:35:25 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Sep 25 16:35:26 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:35:26 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:35:26 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:26 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:35:26 **** avahi-daemon[280]: Withdrawing address record for 192.168.22.1 on wlan0.
Sep 25 16:35:26 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:35:26 **** avahi-daemon[280]: Interface wlan0.IPv4 no longer relevant for mDNS.
Sep 25 16:35:26 **** dhcpcd[379]: wlan0: deleting route to 192.168.22.0/24
Sep 25 16:35:26 **** dnsmasq[481]: no servers found in /run/dnsmasq/resolv.conf, will retry
Sep 25 16:35:26 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:35:26 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:35:26 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:35:26 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:26 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:35:26 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0..
Sep 25 16:35:26 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:35:27 **** dhcpcd[379]: wlan0: soliciting an IPv6 router
Sep 25 16:35:31 **** dhcpcd[379]: wlan0: using static address 192.168.22.1/24
Sep 25 16:35:31 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:35:31 **** avahi-daemon[280]: New relevant interface wlan0.IPv4 for mDNS.
Sep 25 16:35:31 **** avahi-daemon[280]: Registering new address record for 192.168.22.1 on wlan0.IPv4.
Sep 25 16:35:31 **** dhcpcd[379]: wlan0: adding route to 192.168.22.0/24
Sep 25 16:35:31 **** dhcpcd[379]: wlan0: adding default route via 192.168.22.1
Sep 25 16:35:31 **** dnsmasq[481]: reading /run/dnsmasq/resolv.conf
Sep 25 16:35:31 **** dnsmasq[481]: ignoring nameserver 192.168.22.1 - local interface
Sep 25 16:35:33 **** dhcpcd[379]: wlan0: pid 11706 deleted default route via 192.168.22.1
Sep 25 16:35:40 **** dhcpcd[379]: wlan0: no IPv6 Routers available
Sep 25 16:35:49 **** hostapd: wlan0: STA 80:38:96:e9:2a:07 IEEE 802.11: associated
Sep 25 16:35:49 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:35:49 **** hostapd: wlan0: STA 80:38:96:e9:2a:07 IEEE 802.11: associated
Sep 25 16:35:49 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:35:49 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:35:49 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:49 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:35:49 **** avahi-daemon[280]: Withdrawing address record for 192.168.22.1 on wlan0.
Sep 25 16:35:49 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:35:49 **** avahi-daemon[280]: Interface wlan0.IPv4 no longer relevant for mDNS.
Sep 25 16:35:49 **** dhcpcd[379]: wlan0: deleting route to 192.168.22.0/24
Sep 25 16:35:49 **** dnsmasq[481]: no servers found in /run/dnsmasq/resolv.conf, will retry
Sep 25 16:35:50 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:35:50 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:35:50 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:35:50 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:35:50 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:35:50 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0.
.
Sep 25 16:35:50 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:35:50 **** dhcpcd[379]: wlan0: soliciting an IPv6 router
Sep 25 16:35:50 **** hostapd: wlan0: STA 80:38:96:e9:2a:07 RADIUS: starting accounting session 868DF9229968D6F2
Sep 25 16:35:50 **** hostapd: wlan0: STA 80:38:96:e9:2a:07 WPA: pairwise key handshake completed (RSN)
Sep 25 16:35:50 **** dnsmasq-dhcp[481]: DHCP packet received on wlan0 which has no address
Sep 25 16:35:54 **** dhcpcd[379]: wlan0: using static address 192.168.22.1/24
Sep 25 16:35:55 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:35:55 **** dhcpcd[379]: wlan0: adding route to 192.168.22.0/24
Sep 25 16:35:55 **** dhcpcd[379]: wlan0: adding default route via 192.168.22.1
Sep 25 16:35:55 **** avahi-daemon[280]: New relevant interface wlan0.IPv4 for mDNS.
Sep 25 16:35:55 **** avahi-daemon[280]: Registering new address record for 192.168.22.1 on wlan0.IPv4.
Sep 25 16:35:55 **** dnsmasq[481]: reading /run/dnsmasq/resolv.conf
Sep 25 16:35:55 **** dnsmasq[481]: ignoring nameserver 192.168.22.1 - local interface
Sep 25 16:35:56 **** dhcpcd[379]: wlan0: pid 12058 deleted default route via 192.168.22.1
Sep 25 16:35:58 **** dnsmasq-dhcp[481]: DHCPDISCOVER(wlan0) 80:38:96:e9:2a:07
Sep 25 16:35:58 **** dnsmasq-dhcp[481]: DHCPOFFER(wlan0) 192.168.22.35 80:38:96:e9:2a:07
Sep 25 16:35:58 **** dnsmasq-dhcp[481]: DHCPREQUEST(wlan0) 192.168.22.35 80:38:96:e9:2a:07
Sep 25 16:35:58 **** dnsmasq-dhcp[481]: DHCPACK(wlan0) 192.168.22.35 80:38:96:e9:2a:07
Sep 25 16:36:03 **** dhcpcd[379]: wlan0: no IPv6 Routers available
Sep 25 16:36:10 **** hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Sep 25 16:36:10 **** dhcpcd[379]: wlan0: carrier lost
Sep 25 16:36:10 **** dhcpcd[379]: wlan0: deleting address fe80::5857:c295:1403:5e7
Sep 25 16:36:10 **** avahi-daemon[280]: Withdrawing address record for fe80::5857:c295:1403:5e7 on wlan0.
Sep 25 16:36:10 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:36:10 **** avahi-daemon[280]: Interface wlan0.IPv6 no longer relevant for mDNS.
Sep 25 16:36:10 **** avahi-daemon[280]: Withdrawing address record for 192.168.22.1 on wlan0.
Sep 25 16:36:10 **** avahi-daemon[280]: Leaving mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:36:10 **** avahi-daemon[280]: Interface wlan0.IPv4 no longer relevant for mDNS.
Sep 25 16:36:10 **** dhcpcd[379]: wlan0: deleting route to 192.168.22.0/24
Sep 25 16:36:10 **** hostapd: wlan0: STA fc:77:74:23:ec:4f RADIUS: starting accounting session D61CF01C042373D5
Sep 25 16:36:10 **** hostapd: wlan0: STA fc:77:74:23:ec:4f WPA: pairwise key handshake completed (RSN)
Sep 25 16:36:10 **** dnsmasq-dhcp[481]: DHCP packet received on wlan0 which has no address
Sep 25 16:36:10 **** dnsmasq[481]: no servers found in /run/dnsmasq/resolv.conf, will retry
Sep 25 16:36:10 **** dhcpcd[379]: wlan0: carrier acquired
Sep 25 16:36:10 **** dhcpcd[379]: wlan0: IAID eb:20:25:6f
Sep 25 16:36:10 **** dhcpcd[379]: wlan0: adding address fe80::5857:c295:1403:5e7
Sep 25 16:36:10 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv6 with address fe80::5857:c295:1403:5e7.
Sep 25 16:36:10 **** avahi-daemon[280]: New relevant interface wlan0.IPv6 for mDNS.
Sep 25 16:36:10 **** avahi-daemon[280]: Registering new address record for fe80::5857:c295:1403:5e7 on wlan0.*.
Sep 25 16:36:10 **** dhcpcd[379]: wlan0: probing address 192.168.22.1/24
Sep 25 16:36:11 **** dhcpcd[379]: wlan0: soliciting an IPv6 router
Sep 25 16:36:12 **** dnsmasq-dhcp[481]: DHCP packet received on wlan0 which has no address
Sep 25 16:36:13 **** dnsmasq-dhcp[481]: DHCP packet received on wlan0 which has no address
Sep 25 16:36:16 **** dhcpcd[379]: wlan0: using static address 192.168.22.1/24
Sep 25 16:36:16 **** avahi-daemon[280]: Joining mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Sep 25 16:36:16 **** avahi-daemon[280]: New relevant interface wlan0.IPv4 for mDNS.
Sep 25 16:36:16 **** avahi-daemon[280]: Registering new address record for 192.168.22.1 on wlan0.IPv4.
Sep 25 16:36:16 **** dhcpcd[379]: wlan0: adding route to 192.168.22.0/24
Sep 25 16:36:16 **** dhcpcd[379]: wlan0: adding default route via 192.168.22.1
Sep 25 16:36:16 **** dnsmasq[481]: reading /run/dnsmasq/resolv.conf
Sep 25 16:36:16 **** dnsmasq[481]: ignoring nameserver 192.168.22.1 - local interface
Sep 25 16:36:17 **** dnsmasq-dhcp[481]: DHCPREQUEST(wlan0) 192.168.22.39 fc:77:74:23:ec:4f
Sep 25 16:36:17 **** dnsmasq-dhcp[481]: DHCPACK(wlan0) 192.168.22.39 fc:77:74:23:ec:4f 2F-HAYASHI-NOTE
Sep 25 16:36:19 **** dhcpcd[379]: wlan0: pid 12412 deleted default route via 192.168.22.1
Sep 25 16:36:24 **** dhcpcd[379]: wlan0: no IPv6 Routers available
Sep 25 16:40:01 **** CRON[14865]: (root) CMD ([14871] python3 /home/nextpi/Public/Development/python/mqtt_publisher.py 2> /home/nextpi/Public/Development/python/log/puberr.log)

dhcpcdがcarrier acquiredとcarrier lostを繰り返している(だいぶ省略しています)のが気になりますが、
なぜ稀に発生するのか、そしてどう対応すれば良いでしょうか。
ちなみにcandy-pi-serviceを再起動すれば直りましたが、遠隔地で長期運用する
予定なのでインターネットから切れると困るので対応方法を教えていただけると助かります。

ご質問ありがとうございます。
こちらも、以下と関連しているように見受けられます。

このログの後に

[INFO] start_pppd.sh terminated: Exit Code => 0

のようなログはありますか?

また、上記のログより前の時間に以下のようなログがありますでしょうか?PPPがCANDY Pi Liteサービスから起動したものであれば、ログが存在すると思います。

[candy-pi-lite] server_main.<module>: [NOTICE] <candy-pi-lite> serial_port:/dev/ttySC1 (460800 bps), nic:ppp0
[candy-pi-lite] server_main.__init__: [NOTICE] <candy-pi-lite> RESTART_SCHEDULE_CRON=>[] is ignored
[candy-pi-lite] server_main.run: [NOTICE] <candy-pi-lite> Button Extension is terminated.

そのほか、以下のコマンドの結果も教えていただければと思います。

$ sudo systemctl status networkmanager
$ sudo systemctl status modemmanager

なお、対応策としては、上記投稿に回答したとおり、ソフトウェア側で通信モジュールとの接続リトライでの対応となる予定です。

返信ありがとうございます。
server_main.run:と言うログは出ていませんが、それ以外のものは出力されていました。
近辺のログは以下です。
Oct 2 11:11:49 PiZero001 server_main.: [NOTICE] serial_port:/dev/ttySC1 (460800 bps), nic:ppp0
Oct 2 11:11:49 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f RADIUS: starting accounting session 6382C1FA2864084B
Oct 2 11:11:49 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f WPA: pairwise key handshake completed (RSN)
Oct 2 11:11:49 PiZero001 server_main.init: [NOTICE] RESTART_SCHEDULE_CRON=>[] is ignored
Oct 2 11:11:49 PiZero001 dnsmasq-dhcp[450]: DHCP packet received on wlan0 which has no address
Oct 2 11:11:50 PiZero001 dhcpcd[26420]: wlan0: soliciting an IPv6 router
Oct 2 11:11:52 PiZero001 dnsmasq-dhcp[450]: DHCP packet received on wlan0 which has no address
Oct 2 11:11:52 PiZero001 chk_network.sh[28121]: [2020-10-02 11:11:52,695] [chk_network.py.root] [34] [DEBUG] status 0
Oct 2 11:11:54 PiZero001 dhcpcd[26420]: wlan0: using static address 192.168.22.1/24
Oct 2 11:11:54 PiZero001 avahi-daemon[341]: Joining mDNS multicast group on interface wlan0.IPv4 with address 192.168.22.1.
Oct 2 11:11:54 PiZero001 dhcpcd[26420]: wlan0: adding route to 192.168.22.0/24
Oct 2 11:11:54 PiZero001 avahi-daemon[341]: New relevant interface wlan0.IPv4 for mDNS.
Oct 2 11:11:54 PiZero001 avahi-daemon[341]: Registering new address record for 192.168.22.1 on wlan0.IPv4.
Oct 2 11:11:54 PiZero001 dhcpcd[26420]: wlan0: adding default route via 192.168.22.1
Oct 2 11:11:54 PiZero001 dnsmasq[450]: reading /run/dnsmasq/resolv.conf
Oct 2 11:11:54 PiZero001 dnsmasq[450]: using nameserver 203.138.71.154#53
Oct 2 11:11:54 PiZero001 dnsmasq[450]: using nameserver 210.150.255.66#53
Oct 2 11:11:54 PiZero001 dnsmasq[450]: ignoring nameserver 192.168.22.1 - local interface
Oct 2 11:11:54 PiZero001 dnsmasq-dhcp[450]: DHCPREQUEST(wlan0) 192.168.22.39 fc:77:74:23:ec:4f
Oct 2 11:11:54 PiZero001 dnsmasq-dhcp[450]: DHCPACK(wlan0) 192.168.22.39 fc:77:74:23:ec:4f 2F-HAYASHI-NOTE
Oct 2 11:11:56 PiZero001 dhcpcd[26420]: wlan0: pid 30708 deleted default route via 192.168.22.1
Oct 2 11:12:02 PiZero001 dhcpcd[26420]: wlan0: no IPv6 Routers available
Oct 2 11:12:04 PiZero001 systemd[1]: systemd-timedated.service: Succeeded.
Oct 2 11:12:05 PiZero001 mqtt_subscriber.sh[569]: [2020-10-02 11:12:05,598] [mqtt_subscriber.py.root] [32] [DEBUG] status 0
Oct 2 11:13:03 PiZero001 kernel: [350724.988807] sc16is7xx_port_irq: 117666 callbacks suppressed
Oct 2 11:13:03 PiZero001 kernel: [350724.988830] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.988883] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.988925] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.988965] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.989005] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.989173] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.989217] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.989260] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.989302] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:03 PiZero001 kernel: [350724.989342] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070024] sc16is7xx_port_irq: 630 callbacks suppressed
Oct 2 11:13:11 PiZero001 kernel: [350732.070049] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070101] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070173] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070216] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070258] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070299] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070340] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070380] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070420] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:11 PiZero001 kernel: [350732.070459] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079083] sc16is7xx_port_irq: 235524 callbacks suppressed
Oct 2 11:13:15 PiZero001 kernel: [350737.079106] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079159] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079202] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079243] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079282] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079322] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079361] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079401] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079441] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:15 PiZero001 kernel: [350737.079480] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089077] sc16is7xx_port_irq: 230520 callbacks suppressed
Oct 2 11:13:20 PiZero001 kernel: [350742.089100] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089153] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089196] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089239] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089280] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089319] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089360] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089398] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089439] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:20 PiZero001 kernel: [350742.089479] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099082] sc16is7xx_port_irq: 233401 callbacks suppressed
Oct 2 11:13:25 PiZero001 kernel: [350747.099105] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099159] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099201] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099241] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099282] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099323] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099361] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099402] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099441] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:25 PiZero001 kernel: [350747.099479] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109086] sc16is7xx_port_irq: 234312 callbacks suppressed
Oct 2 11:13:30 PiZero001 kernel: [350752.109110] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109165] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109207] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109248] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109288] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109327] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109366] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109404] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109444] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:30 PiZero001 kernel: [350752.109484] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119073] sc16is7xx_port_irq: 230668 callbacks suppressed
Oct 2 11:13:35 PiZero001 kernel: [350757.119096] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119150] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119194] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119234] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119275] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119314] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119353] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119392] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119431] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:35 PiZero001 kernel: [350757.119470] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129063] sc16is7xx_port_irq: 233313 callbacks suppressed
Oct 2 11:13:40 PiZero001 kernel: [350762.129086] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129141] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129185] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129226] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129266] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129307] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129345] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129385] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129426] sc16is7xx spi0.1: ttySC0: Unexpected interrupt: 0
Oct 2 11:13:40 PiZero001 kernel: [350762.129464] sc16is7xx spi0.1: ttySC1: Unexpected interrupt: 0
Oct 2 11:14:23 PiZero001 chk_network.sh[28121]: [2020-10-02 11:14:23,300] [chk_network.py.root] [176] [ERROR] [Errno 110] Connection timed out
Oct 2 11:14:24 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:24 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Oct 2 11:14:24 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:24 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Oct 2 11:14:24 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:24 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Oct 2 11:14:24 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:27 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Oct 2 11:14:27 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:27 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Oct 2 11:14:27 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:27 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Oct 2 11:14:28 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:29 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: disassociated
Oct 2 11:14:29 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f IEEE 802.11: associated
Oct 2 11:14:29 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f RADIUS: starting accounting session 1EF6D5F744C33E42
Oct 2 11:14:29 PiZero001 hostapd: wlan0: STA fc:77:74:23:ec:4f WPA: pairwise key handshake completed (RSN)
Oct 2 11:14:29 PiZero001 dnsmasq-dhcp[450]: DHCPREQUEST(wlan0) 192.168.22.39 fc:77:74:23:ec:4f
Oct 2 11:14:29 PiZero001 dnsmasq-dhcp[450]: DHCPACK(wlan0) 192.168.22.39 fc:77:74:23:ec:4f 2F-HAYASHI-NOTE
Oct 2 11:15:16 PiZero001 pppd[30431]: No response to 4 echo-requests
Oct 2 11:15:16 PiZero001 pppd[30431]: Serial link appears to be disconnected.
Oct 2 11:15:16 PiZero001 pppd[30431]: Connect time 3.5 minutes.
Oct 2 11:15:16 PiZero001 pppd[30431]: Sent 371804 bytes, received 323690 bytes.
Oct 2 11:15:17 PiZero001 dnsmasq[450]: reading /run/dnsmasq/resolv.conf
Oct 2 11:15:17 PiZero001 dnsmasq[450]: ignoring nameserver 192.168.22.1 - local interface
Oct 2 11:15:22 PiZero001 pppd[30431]: Connection terminated.
Oct 2 11:15:23 PiZero001 pppd[30431]: Serial link disconnected.
Oct 2 11:15:24 PiZero001 pppd[30431]: Modem hangup
Oct 2 11:15:24 PiZero001 pppd[30431]: Exit.
Oct 2 11:15:24 PiZero001 candy-pi-lite: [INFO] start_pppd.sh terminated: Exit Code => 16

教えていただいた2つのコマンドは今度現象が発生した時に試せばいいですか。

ログのご提示ありがとうございました。

確認させていただきたいのですが、回線切断後(上記ログの[INFO] start_pppd.sh terminated: Exit Code => 16のメッセージが出た後)、CANDY Pi Liteは再接続しますか?

回線切断自体は、ご契約の通信回線業者(キャリア)によって定期的に行われることがありますので、切断自体は問題ありません。しかし、再接続しないとなるとソフトウェア側の競合の可能性を検討する必要があります。
もし可能であれば、以下のリストの最新バージョンにあるOSイメージをお使いいただいて動作を確認していただけますでしょうか。

https://forums.candy-line.io/tags/os

その上で、状況が再現するかどうか、また、再現した場合は、セットアップしたコマンドの内容も合わせていただけますとこちらで同じ状況を作りやすくなりますので可能な範囲で(独自のプログラムなどは開示不要です)お知らせいただければと思います。

なお、先に提示した2つのコマンドは、CANDY Pi Liteソフトウェアに直接競合する可能性のあるサービスであるため、既存の環境でご利用中であれば停止と削除をお願いできればという意図で現在利用中かお聞きするためにお願いしておりました。
専用OSイメージをお試しいただく場合は、これらのサービスは入っておりませんのでお試しいただく必要はありません。

まとめますと、

  1. 可能であれば専用OSイメージで環境を作って動作を検証していただけますか
  2. 問題が再現した時は、セットアップ手順を含めてお知らせください

お手数をおかけしますが、ご検討のほどよろしくお願いいたします。