Been having this issue for the past year or so. May have possible found the fix tonight. I run Plex on my unRaid server in docker(Linuxserver container) and it has been locking up every 3 hours for 10 mins like clockwork. Daily.
I had checked every scheduled task, tried every other container, tried disabling chapter thumbnail creation etc and nothing would work.
Dawned on me today, I have the Dynamix SSD trim plugin installed which runs every….3 hours! Completely forgot about it. Changed it to run in the middle of the night and I haven’t had a lock up in the past 12 hours.
Hope this can help someone!