An Exchange bug is causing iOS 6.1 devices to continuously loop when syncing a recurring calendar meeting invitation to Microsoft Exchange and this way crippling battery life and performance. Yesterday Microsoft offered workarounds for this bug, and today Apple announced on its support page that it has identified the problem and is working on a fix.

Apple has identified a fix and will make it available in an upcoming software update. In the meantime, you can avoid this bug by not responding to an exception to a recurring event on your iOS device. If you do experience the symptoms described above, disable then reenable the Exchange calendar on your iOS device using the steps below.

1. Go to Settings > Mail, Contacts, Calendars
2. Select the Exchange account from your Accounts list.
3. Turn the switch for Calendars to OFF.
4. Wait ten seconds.
5. Turn the switch for Calendars back to ON.

Source [MacRumors and iDB]