Yeah me too. I had the same problem happen to me when I had to get up for work. Alarm activated to go off at 0430 am, luckily my body clock woke me up 30 minutes after to find that the alarm icon was still sitting in the status bar.
Surprised I'm not the only one who experienced this...I'm suspecting it may have something to do with new year's just passing.
Testing the alarm so far and seems to be working fine. See if it works tomorrow morning.