iPhone alarm doesn't go off sometimes or goes off on the wrong time.
First example, last night I changed my alarm from 7:00am to go off at 6:00am. I woke up at 6:50 without any alarm. Then in my scramble to get ready, my alarm goes off at 7:04am??? I'm completely baffled as to why this happened. This hasn't been my first problem with the alarm either. I've had times where my alarm just hasn't gone off at all and made me late for class. Everytime the night before, I'd make sure the volume was on max, and it wasn't on silent mode. This is a serious problem and if I had a job, I know I couldn't rely on my phone to go off at the proper time.
iPhone 4 (8GB), iOS 5.1