I have something similar to this going on...
I have 3 Alarms Set for every weekday.
4:25PM, 6:25PM and 8:55PM these are my breaktimes at work and if I don't have an alarm I tend to work through my breaks which the union gets their panties in a bunch about.
So my issue is that the 4:25 Alarm goes off 3-5 times at once. As if the alarm is duplicated, I have cleared out all alarms rebooted the phone re-created the alarms and this is still happening. running 8107 on my Focus S this never happened on my SGH-i917.... wierd bug. I have to hit "Dismiss" like 10 times to get the alarm to shut off.
Samsung Focus S | SGH-i937 | Windows Phone 7 build 8773
Samsung Focus | SGH-i917 | Windows Phone 7 build 7720 - Backup
Samsung Epix | SGH-i907 | Windows Mobile 6.5 - Retired
Samsung Blackjack | SGH-i607 | Windows Mobile 6.0 - Retired
Motorola RAZR v3 (Black) - Retired