AD object restore question

[mlange]

Short and skinny, we had a user leave at the end of July but come back this week. We restored his account from backup, and due to our retention policies in O365 we figured everything up there would restore on its own when his account got synced up. Unfortunately that didn't happen. After digging around we found that his objectGUID is now different, and the account is showing as created on the day of restore. Is this the expected action and a lack of knowledge on our part or did we do something wrong?

[foggy]

Basically, if the object had still resided in a temporary container where all the deleted AD objects are kept for some time after deletion, Veeam B&R would have been able to restore it with the original objectGUID by simply moving it back to production. The restore log should tell what did actually occur during the restore and why did the object get a new ID value.