Last night, I had picked up the phone, pressed the power, and noticed an incoming call without notification coming at me. When the call ended 30 minutes later, my screen stayed dark. Power button was unresponsive. No LED or anything. Completely dead-looking. No indication it was still on or not. Took the battery out/in and it rebooted, which makes me think it had been on least. First time that's happened. Anyone else?