Calendar Error Connecting to Exchange - Erroneous Invites

I was hoping that 10.8.2 would fix some existing Calendar problems in connecting with Exchange. It looks like some issues might be resolved, but this one remains: when an appointment time is reached, an error pops up in the Calendar that says:

“Test” had invitees not recognized by the server.

You entered an invitee that wasn’t recognized by the server.

In Outlook on a PC, the appointment has been changed to one that expects an invitee to have been selected, but where the invite field is blank. You have to hit "cancel invitation" to fix the appointment, which then works as expected in Calendar on the Mac.

Fix Later or Edit Event are the options given for the error, neither of which seem to make any difference. As far as I can tell, once the error pops up Calendar starts having problems syncing again.

Really, Calendar on Mountain Lion 10.8.2 is utterly useless when connecting with Exchange. This state of affairs has existed since Lion, I'm pretty sure, and it's frustrating. I do wish Apple would get on top of this and resolve it.