Is there an error when "upgrading library" constantly reverting back to

Plex DocsYour Media
Naming & Organizing TV Show Files
Naming & Organizing Movie Show Files

The new scanners/agents are more stringent on enforcing Plex naming and organization requirements.

Rename/reorganize your media, especially TV shows, to align more closely with the Plex documentation.

You may need to Plex Dance the media after renaming the files.

Change one show to make sure things work correctly. If so, proceed with the rest.

Apr 20, 2022 04:28:02.444 [0x7fa470723b38] ERROR - IntroDetector: Failed to get metadata for: /mnt/media/tv/It's Always Sunny in Philadelphia/Its.Always.Sunny.in.Philadelphia.S08.720p.BluRay.DD5.1.x264-CtrlHD/Its.Always.Sunny.in.Philadelphia.S08E06.Charlies.Mom.Has.Cancer.720p.BluRay.DD5.1.x264-CtrlHD.mkv

/mnt/media/tv  <-- folder added to TV show library
.../It's Always Sunny in Philadelphia (2005)
....../Season 08 <-- "Season" in English, two digits for number
........./It's Always Sunny in Philadelphia s08e06 Charlies Mom Has Cancer [misc info].mkv

Tools to assist with renaming media: