SOLVED: Some Primary Posters Are Lost Without Fail

[TheDreadPirate]

For now, disable the library refresh job and refresh manually when needed. It's not clear from the log WHY Jellyfin is removing and re-adding some of these individual movies.

You can try enabling debug logging and wait for the problem to happen again. This would require that the refresh job be left running.

C:\ProgramData\Jellyfin\Server\config\logging.default.json

Change "Information" and "Warning in the top section to "Debug". This change should take effect immediately. Once this happens again, zip up the log and attach to a forum post. Zipping is required since the log will likely be very big.