[DaveBlake]

Thanks for that. I now wonder if the issue is scraper related, you are scraping on library update, something I didn't do. I will do some more testing.

Do you have "Prefer online information" setting enabled?

Also having "ALBUM ARTIST" and "ALBUMARTIST" tags is a little odd. Kodi will process both, but the second one it finds will overwrite the first so that should not be the issue.