http://fiftyninety.fawmers.org/song/42178 - shows up twice in my profile, and also credits me with an extra song. I added two collab partners... and that's when it happened.
It's prolly coz my collab partners are doubly awesome.
I've had this happen before. IIRC it was solved by only one collaborator claiming a collaboration. In my case the original author of the song took me off as a collaborator. I left myself on. He had two songs , the original uncollaborated and the collaboration. I just had the collaboration. Hope it helps.