[DaveBlake]

While I was thinking about this @Karellen actually did some conclusive testing (good on him, receive todays gold star).

Having smart playlist files (.xsp)  in a media source folder that gets scanned into the library will result in duplicate albums.

This is an unusual occurance, smart playlist files created by the user are saved in the userdata folder, and that is generally not added as a music source. It is possible that this is the first time a user has scanned .xsp into the library. However now I know this can happen I will look at ensuring future versions of Kodi are robust enough to avoid the issue. The resulting extra albums point at the same music files as the correct albums (a diagnostic clue for any other ocassion)

So @BikerDude change the music source as I suggested in my previous post, so that your "playlists" folder with both .xsp files and poorly tagged files does not get scanned. You still have mixed tagged albums to fix, but the scanning of .xsp files was a big contributor to your duplicates.

In fact please do all I ask in the previous post, just to confirm things and enable me to give feeback on your tagging generally.