According to CVG, a bug has been plaguing PlayStation 3 owners causing their Trophy data to become corrupt.
The error occurs when users change their PSN ID or password. Reported games that this bug has affected include, WipEout HD, Burnout Paradise, LittleBigPlanet and Pain.
Sony Computer Entertainment (SCEE) Community Manager "MusterBuster" has made a post on the official PlayStation forums stating, "A fix is on the way, but I don’t have an ETA yet."
Until Sony has released a patch for the issue, it’s best to keep your PSN ID’s and passwords the same. Perhaps this will help tone back the game sharing. Stay tuned for more details.