Apple has announced that a fix for the iOS 6.1 Exchange syncing bug is on the way. Apple also has a workaround it says you can use until the update is available.
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.
Apple then advises users to go to “Mail, Contacts, Calendars” under “Settings,” select the Exchange account from the accounts list, then turn the switch for “Calendars” off, wait 10 seconds and then turn it back on.
The bug causes iOS 6.1 devices to continuously loop when syncing a recurring calendar meeting invitation to Microsoft Exchange.
Apple did not specify a timeframe for when the fix for the bug will be released.