The alarms I have scheduled never go to "OFF" automatically. However, I noticed when ever you have a notification pop-up on the screen (I.E. Facebook Notification, 20% Battery Remaining, 10% Battery Remaining), the alarm will not go off.
This also happened with my 2G, 3G and 3GS. I guess Apple still hasn't fixed this bug.
This also happened with my 2G, 3G and 3GS. I guess Apple still hasn't fixed this bug.