Has anyone had this problem? I will make a phone call and it no matter if I'm using a bluetooth or the iPhone itself to make the call some times it will switch to to speaker on its own and will mute the mic on its own and I have to reset the iPhone. It's annoying. I've restored the phone twice and the problem still comes back every time. I have a Sprint iPhone 4S if that helps. I'm probably going to apple on Tuesday to get a new one.