Sorry to bring this post back from the dead, but as this was the only post on this topic I found in google, and there is no for sure solution... All I did was quit to the dashboard, load the game back up, then I went to the load Game screen and picked the beginning of the level it started screwing up on (3rd) and it loaded and everything was normal again. Then I loaded up the furthest save and it was all working.
I am not sure all that is necessary, but that is all I did and thats what worked. Once again, sorry for bringing this post back, but I am sure some people may find this useful if they get stuck. (instead of going buy a whole new game, or clearing the cache) :P