I don’t want to criticize the developers ;), but Picard 3 doesn’t work well with CAA. There are always dozens (sic!) of red discs appearing in Picard’s right panel. And these are always different albums, there is no rule. I’ve split my 16,000 files into 4 parts. And that doesn’t even help. With 4,000 files, there are always about 10 red discs. I’ve already written about this on the forum. The funniest thing is that Picard shows a CAA error, but finds the cover. It seems OK, but it disrupts the Picard experience.
My earlier thread: https://community.metabrainz.org/t/lots-of-errors-red-discs-and-hidden-errors-in-picard-3/814367