I've had more than a few glitches occur with my iphone 6, but this one may be the oddest: There I was this evening, minding my own business, when I hear an alert go off. So I pull my phone out of my pocket to see what it is but it's dark. I turn it on and see nothing at all. No messages, no notifications or anything else. 20 minutes later it happens again, only this time it's a different alert sound, an alert sound I've assigned to a particular friend. So I pull out my phone expecting to see a text from this friend and nothing. No sign of any activity at all. Anyone heard of such random alerts going off, or what this might portend?