Symptoms
You have migrated a user mailbox with Hybrid remote move to Microsoft Office 365 from Exchange Server 2019 or Exchange Server 2016. When you try to convert this migrated remote mailbox to a shared remote mailbox, you receive the following error message:
WARNING: An unexpected error has occurred and a Watson dump is being generated: remoteMailbox.RemoteRecipientType must include ProvisionMailbox.
Resolution
To fix this issue, install one of the following updates:
The Cumulative Update 3 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019.
The Cumulative Update 14 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
References
Learn about the terminology that Microsoft uses to describe software updates.