I've got Exchange 2003 and Outlook 2007 running. Right now, user A cannot see several items on user B's shared calendar. There are many other items on user B's calendar throughout the week that are visible, but 1 is missing. There are a few others in the coming month that we cannot see either.
I go to several other machines, users C through H for example and they can all see user B's calendar entry that user A cannot see. I've tried toggling cached mode. Deleted user profile and recreated. Clearing offline cache. I even logged onto another machine (one user A has never used before) as user A and the calendar items are still missing.