This is looking almost perfect.
Are you 100% certain that your tv sahow library has been pointed to the folder
/mnt/media/media_server/Media/Television
only? Not a single folder level above, nor below it?
To remove ambiguity, insert the release year of the show, like this
/mnt/media/media_server/Media/Television/Black Mirror (2011)/Season 1/Black Mirror - S01E01 - The National Anthem Bluray-1080p.mkv
If you can rule out an access permissions issue,
perform the Plex Dance with the whole show.
If that still doesn’t change things, see if your database file is damaged: GitHub - ChuckPa/DBRepair: Database repair utility for Plex Media Server databases
Are you looking at your server with a tv app , or the mobile plex app?
I recommend using the web app first to check for proper recognition.
The other apps may use more aggressive caching, which can delay fresh info from appearing for a while.
