That would really suck if it was true. I dont think it is though, I think it is some kind of glitch. I have 4 xboxes, but I put this particular game on my memory stick that I take back and forth between them. I've unlocked achievements on 2 different boxes for this game but they seem to have stopped altogether. I will be able to try again on the original box that my memory stick was plugged into when I bought it on sunday, I will try again and let you know how it goes.