In the system logs I found several restarts of audio, cli and dns (same as for SSH addon).
21-05-02 16:28:58 WARNING (MainThread) [supervisor.misc.tasks] Watchdog found a problem with PulseAudio plugin!
21-05-02 16:28:58 INFO (MainThread) [supervisor.plugins.audio] Starting Audio plugin
21-05-02 16:28:58 INFO (SyncWorker_4) [supervisor.docker.interface] Cleaning hassio_audio application
21-05-02 16:29:01 INFO (SyncWorker_4) [supervisor.docker.audio] Starting Audio homeassistant/armv7-hassio-audio with version 2021.04.0 - 172.30.32.4
21-05-02 16:29:07 WARNING (MainThread) [supervisor.misc.tasks] Watchdog found a problem with cli plugin!
21-05-02 16:29:07 INFO (MainThread) [supervisor.plugins.cli] Starting CLI plugin
21-05-02 16:29:07 INFO (SyncWorker_2) [supervisor.docker.interface] Cleaning hassio_cli application
21-05-02 16:29:08 INFO (SyncWorker_2) [supervisor.docker.cli] Starting CLI homeassistant/armv7-hassio-cli with version 2021.04.1 - 172.30.32.5
21-05-02 16:29:15 WARNING (MainThread) [supervisor.misc.tasks] Watchdog found a problem with CoreDNS plugin!
In portainer I found the error was caused by
exec: fatal: unable to exec bash: Exec format error
I’m not so sure what was done with the armv7 images - but I was able to workaround by installing armhf images as armv7. Is it only me - or do the armv7 no longer work with raspi 4?