My phone is on its way back to me from it's 2nd RMA for this issue. They never tell you what it was until you get your package back but I'll update this thread if it's fixed!
I have same problem, I sent it to service center and they factory reset my phone. That didn't fix it. Now I have to send it back again. Kinda annoying. If I didn't have a backup phone I'd be furious.