Sand is getting behind the flash lens!
Just a heads up if you carry your Tour like I do in my pocket without a case. Even with a case, I suspect there is a slot in the top of the case too. I use the Verizon screen protector and prefer to just pop the Tour in my pocket with no case.
When I was trying to diagnose why some of my flash pics come out with a yellow tinge I looked at the flash lens with a lighted magnifier . . . What I see is many sand like specs of debris building up on the inside (backside) of the flash.
It looks to me like it's getting in by the slot at the top of the Tour.
No big deal operational wise yet, but if you have your phone in your providers store let them clean the flash lens while you are there if you see debris building up like mine is!