Pandora bug

As some of you know, I'm a Pandora heavy user, I think it is better than Last.fm, and I think it will get a lot better. Of course it still has lot's of problems, and I know some of them... But now I've just stumbled upon a curious one.
I indicated to Pandora some weeks ago that I like Steve Roach. Now, I've started a new "session" on Pandora and this has been the songs it gave me:

• Steve Roach - Flatlands
• Steve Roach & Vir Unis - Born of Fire
• Byron Metcalf featuring Steve Roach - Raven Medicine
• Steve Roach & Robert Rich - Soma
  

OK, now, I'm not complaining - I'm liking to listen to them, but Pandora algorithm gave me this four tracks as something like "similar tracks from different artists". OK, the "Artist name" on the track is different, but the Artist itself is the same.