@geokie said:
Must be something really weird, that didn’t help either (but thanks for the suggestion!).
I have even gone so far as to remove the files, restart the server and re-add them. Marked them as watched, restarted the server, and marked them as unwatched etc. Still no joy…
OK. Try a full Plex Dance. https://forums.plex.tv/discussion/comment/908454/#Comment_908454
Also, add to that an “optimize database” while the series is not in the Plex library structure.