Before doing anything else:
Enable Debug Logging, Disable Verbose Logging:
Settings/General
Then I would rename those files without all the nonsense at the ends.
Like that - or now that we’re grabbing at straws:
Attack on Titan/ ....Season 03/ .........Attack on Titan - s03e14.mkv
Let’s remove all possibilities for strangeness - and let Plex do it’s best.
AFTER renaming:
DO ANOTHER PLEX DANCE!
If Plex fumbles the show, Fix Match.
If Problems persist prepare to download those fresh logs we just made - when requested to do so.