My 920 has recently started dropping calls, almost every other call. It just cuts out and returns to its previous screen (whatever it was, usually a contact) without displaying the usual "Call ended" splash screen. It's almost as if the "phone call" app just crashes without any sort of graceful exit - is this happening to anyone else? I know it's not a signal/reception issue because I'm in my house which has always had a very strong AT&T signal.