Possible Fix but not fully tested yet
Spent time on the phone with Apple rep again this AM.
Renaming the Synch Services folder to force a completely new one seems to have fixed the problem for now.
Go to Home>Library>SynchServices and rename that entire folder to something else.
Restart the mac
Try synch again.
You will have to cancel any automatic syncs and re-create all your synch services stuff but once I did that my calendar issues are solved for the moment.
Will keep track and see if it causes more problems later as I rebuild my iPod including 2 apps that sync over wifi, Evernote & Omnifocus
Oogie McGuire - Mac, iPhone & Omnifocus
OogieM on Twitter
Paonia, CO USA