I cannot tell you how many times I’ve encountered scenarios where “this data looks wrong.” Well… can one ensure that it is being retrieved and displayed correctly from the storage media that it resides on in the first place? Are you viewing/validating the data in question correctly? Whatever client/method you are using to review your data – that is suspect and its integrity is in question.
It is technically possible for bits to flip, but that’s also why we have checksums on disk. I’m sure there are people who have experienced storage corruption that changed just enough to cause problems but not enough to be noticeable, but Andy is right on the money.