Microsoft recently changed a mechanism in O365, and therefore has impacted our typical functionality.
The following will impact customers performing a 2 way Public Folder synchronization using the MAGE PF Synchronization, with Migration
Manager for Exchange. Migration Manager relies on item’s “UniqueID” for source & target items. This value is stored in the project database for tracking purposes. Currently, in Office 365 Migration Manager requests the UniqueID of each item, for a 2 way synchronization, and is provided a different ID for the item than initially provided when it was created. As the target item has a newly generated UniqueID than Migration Manager has stored, this item is considered new and synchronized back to the source, thus creating duplicates.
We are working with Microsoft on a solution and hope to have one soon.