Thanks for looking into this. Unfortunately, this didn't seem to make any difference. I verified the extra config file and started/stopped the array twice to double check. Multiple docker containers (plex, sonarr, radarr, nginxproxy, nzbhydra, bitwarden etc.) refuse to start unless I switch back to /mnt/cache/appdata. They all give some variation of "database corrupted" error.
What I don't understand is why I didn't have any issues with 6.7.0 (where these first user reports started popping up), and only after I upgraded to 6.7.1.
Let me know if there are some other steps I can take.