From another thread: https://forums.plex.tv/discussion/158487/plex-incorrectly-identifying-tv-episodes/p1
@OttoKerner said:
Perhaps you renamed the files to a conforming name schema only after they were already (incorrectly) matched.If this is the case, you still need to perform the ‘Plex Dance™’ to erase their checksums from the plex database.
[optional: disable the SubZero plugin if installed]
- move all files for the show out of ‘sight’ of plex
- update library (
not ‘force update’not ‘Refresh all’)- empty trash
- clean bundles
- double check naming schema and move files back
- update library
[optional: re-enable the SubZero plugin if installed]
in this order