First of all, let me describe my setup for music. I have a "Music" library pointed at iTunes/iTunes Media/Music — not sure if it works well now, but when I started the direct iTunes library option was unreliable. I often add music to my iTunes library with generic names and wind up tagging them within iTunes. Previously this has led to Plex scanning the folder as I worked and adding the generic names as well as the real ones but eventually catching up.
With this latest release I am finding that the generically named tracks/files are remaining in the library, unplayable of course, interleaved with the real files. So, a 12-track album shows 24 tracks with two for each track number. I have given it a couple of days and still no self-correction, emptying trash fails, library rescan does not help.