Thanks so much for having a play with this nibbles - is it the case for you if you use the TS02 tag from Picard on an mp3 as the only artist sorting mechanism that you see the Aretha album under F rather than A in Plex?
I did a Plex dance with a solo artist with one album (manually move the files elsewhere, scan files, empty trash in plex), and inserted a TS02 tag in foobar2000 with ‘lastname, surname’ before putting the files back. No luck unfortunately. However, when I tried the same thing with ARTIST-SORT with the hyphen, it DID work. So thank you for figuring that one out!
