Please refer to these threads (caution they’re long, but worth the read because they’re highlighting several fallacies): All of my "Various Artists" albums changed Artist name
and Manual Album Artist Changes Unmatches Music
All of this has nothing to do with Plexamp specifically but with the Plex server and how it is indexing your music.
All follow-up discussion should therefore happen in the https://forums.plex.tv/c/plex-media-server/metadata-adding-files/124 subforum, instead of here.
