It looks like its to do with some update FF must have been makin. As im an admin, I can do things that wouldnt always be possible for everyone, such as download tracks when others cant. Something to do with whether a track is visible and/or approved has been added (hence the blank 'status'), and it appears to have caused this whole issue.
I have tried switching the status around with some SQL, but it had odd effects, so I am going to leave it alone now and let FF look at it, when he comes online.