So Apple have released a fix for the recent issue with over logging issue on Exchange 2010.
Here’s the link: http://support.apple.com/kb/TS4532
But for the lazy here’s their fix:
- Go to Settings > Mail, Contacts, Calendars
- Select the Exchange account from your Accounts list.
- Turn the switch for Calendars to OFF.
- Wait ten seconds.
- Turn the switch for Calendars back to ON.