What external tools are you using with your server?
Did you add the show into the library, and then later changed the metadata agent of that library?
Are the videos in MP4 containers? If so, you better disable “Prefer local metadata” in the properties of this tv show library.
Have you checked your database for the recent-ish DB bloat issue? Library.db size more than doubled in latest version - #375 by ChuckPa
Have you performed a thorough DB repair? GitHub - ChuckPa/DBRepair: Database repair utility for Plex Media Server databases
