In movies, it’s rather easy to individually change the remote metadata language that Plex is gonna use for description and title (Pencil icon, Advanced, Metadata language).
But for TV Series i did not find such a setting. About 30% of my tv series are not in english so i want to be able to tell Plex to use metadata accordingly, not for the remaining 70% that are in english.
Don’t forget to Refresh Metadata of the whole library.
Then check the episode order of each show. Because the order from TheMovieDB.org is used by default. If you named your files after the order on TheTVDB.com (which can sometimes be different), you need to set the episode ordering to TheTVDB in the properties of the affected shows.