In the library you’re seeing this
3 dots next to the library → Manage Library → Edit → Add Folders
Make sure you don’t have an old path added to that library. I had moved some content around on my file system one time and forgot to delete the old path.
Inside one of the season folders you can also click an episode. 3 dots → get info to see if there’s a 2nd copy hanging around in the background for those files.
I hate to suggest it, but if none of that pans out you may have to do a Plex dance and see if that cures it
Otherwise, you can take a look in your logs and make sure you don’t have some kind of database corruption going on
Download the zip to your file system and open it. Go to this file
IDK what you use but in Windows I open it using notepad and go to “edit → find”
Search “corrupt”
Then do a new search for “malformed” and see if you get any hits
