This is very interesting. I have a very similar issue.
-The band Genesis does not appear in the artist list (but I have a bunch of their albums.
- all the Genesis albums appear under the artist name "Roger T. Matte/Yngve Guddal/Roger T Matte".
- I deleted "Roger T. Matte/Yngve Guddal/Roger T Matte" from OrangeCD and forced a sync.
- I re-added "Roger T. Matte/Yngve Guddal/Roger T Matte" to ORangeCD, changed their name to "Roger T. Matte & Yngve Guddal" and forced a sync.
- Nothing changes online in Racks & Tags. In the artist list "Roger T. Matte/Yngve Guddal/Roger T Matte" is still there, and Genesis is not.
- Like innerspaceboy, when I float the cursor over the artist names the URL is always the artist name, except for "Roger T. Matte/Yngve Guddal/Roger T Matte" which is ..../artists/3895890/

Clue: Roger T. Matte & Yngve Guddal do covers of Genesis tunes, for a CD called Genesis for 2 Grand Pianos. So their songs share titles with the songs on some of the Genesis albums.