Picard skipping album artist tags on songs added after a save

Within the same album, if I save e.g. 12/13 tracks, then add the 13th track later and press save again - a tag field (album_artist) or (Album Artist) gets completely ignored and not applied to the 13th song)

Album lookup without any songs applied (Note the consistent album artist fields):

Album lookup & save with 12/13 songs:

The issue arises when adding the forgotten song:

To my understanding, if I’m adding the song into the lookup it should adjust and match the metadata of the looked up song, but it doesn’t & skips the tag, resulting in my album artist being duplicated:

The issue as far as I can tell is that it doesn’t create an additional tag for the new song for whatever reason.

I’m pretty sure this is an error on my part and I’m misunderstanding something but I’ve had this happen on multiple albums now (with post-saving songs being added), and it doesn’t fix itself if I completely close the program and treat it like a fresh album ready to tag.

It could be a bug, you should open a ticket (see General Troubleshooting — MusicBrainz Picard v2.13.3 documentation ).
It is very important you provide a debug log (because it will contain information we need to reproduce the issue, and also details about the version you are using).

Does it still happen if you save the album, add the missing file, then Refresh the album and save it?