Symptoms
Administrators can’t start and stop the migration of individual public folder mailboxes within migration batches for on-premises Microsoft Exchange Server 2019 or Microsoft Exchange Server 2016. If migration objects are missing for certain public folder mailboxes within a batch, administrators can successfully re-create the objects only after they apply unsupported workarounds.
Resolution
To fix this issue, install the following updates, as appropriate:
Cumulative Update 12 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
Cumulative Update 23 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016
