When I upgraded to Android 4.1.1 Jelly Bean via OTA earlier this month, the bundled Calendar application was upgraded to version 4.1.1-398337. After this, a bug appears.
The bug only happens when default reminder time is set to None.
After adding a new event, everything seems fine. Go into the event screen, everything is normal. But when you exit to month view mode, or exit the calendar, then go back to see the event, two reminders are set up automatically for you. One for (Android) notification, one for e-mail, both 10 minutes before the event commence.(See second last paragraph)
If you set a default reminder time other than "None", The reminder will be normal: just one notification reminder of designated time.
Today, searched for the problem and found someone mentioned something with synchronisation. So, I logged in to Google Calendar on PC for the first time. Midway through the setup wizard is the default reminder setting. I immediately recognised some familiarities: a ten minute notification to phone and e-mail. I clear these two, save it, and create new events on my phone. No reminders, good.
Then I create a new event for my other Google account, which I have never logged in to calendar on PC before. Not surprisingly, the unexpected reminders are here again.
I changed the default reminder setting in Google account to 10 hours, then create a new event again on the phone. After syncing with the server, a 10-hour reminder appeared on the phone. Apparently, the initial 10-minute reminders came from the server, too. It looks like changing to month viewing mode or exiting the application will trigger the reminder generation, but it turns out it is just the delay of synchronisation.
There seems to be two independent reminder systems in the 4.1.1 Calender application: one on the phone, one from the server. There is no way on phone to change settings on server, and vice versa, thus the annoyance I faced.
