When trying to update the CustomAttribute5 (added pre Office 365 with AD Sync) for a user I get the following error:
The operation on mailbox "xxx" failed because it's out of the current user's write scope. The action 'Set-Mailbox', 'CustomAttribute5', can't be performed on the object 'xxx' because the object is being synchronized from your on-premises organization. This action should be performed on the object in your on-premises organization.
The only thing that is on-premises is the ADUser info and it does not contain any of the CustomAttribute fields. Those are only in the Mailbox area and I cannot access that from the AD.
What are my options?