Sorry, no help here, but I also have problems with calendar/events after update to PR1.3.

I updated OTA and have Callendar Widget installed. After update some events generate alarm, but other not. I cannot see any pattern here; the only thing is that events repeated every day are more prone to missing alarms, and events with more time between them (once a week, etc.) have more chance to generate alarm. If I come with test case I will fill bug report, but for now it is rather annoying.