Someone else on the forum got theirs exchanged for a new one. I would suggest head out to the apple store and get a new one. I haven't had any yellowing... I don't think it's a software issue.
My wife's was yellowing. Went to the Apple store. They tried to tell us the flash was reflecting off the edges of the case that are around the flash/camera. They still exchanged it.
I get a yellow/ jaundiced skin look on my photos taken indoors in lower light with the flash. Videos, too. It did this before and after I installed my Otterbox Defender.
Outdoors, the pics are great.