Duplicate and Disappearing appointments

Question

We have a CRM 4.0 installation and are having an intermittent problem where some appointments are being duplicated (Cloned).   The duplicate appointments are nearly identical to the original ones except the custom CRM fields will always be empty and the Owner of the appointment may be switched with one of the Attendees.  Appointments that get duplicated can be Open or Closed appointments.

We are also having a related problem where intermittently, some appointments disappear from CRM (and Outlook).   We checked the CRM database and found the deleted appointments flagged for deletion (activitypointer .deletionstatecode = 2).   I did find a posting that says this behavior could be caused if a User’s email is found in an Account, Contact or Lead entity and I made sure that is not the case.

We’re suspicious these problems might be related to the Outlook CRM client when appointments get synchronized between Outlook and CRM.  We do not have any plug-ins or workflows that would cause duplicate appointments and we made sure the Outlook client is on UR 21 and all Outlook profiles are correct and properly configured.

Has anyone come across something similar?

Thanks,

--Raul