Assume, I move a mailbox from one database to another. Within the retention period, get-mailboxstatistics will return mailbox information for both databases ie. there will be two entries for the same mailbox. But get-mailbox cmdlet will return only one mailbox information for that particular mailbox. Will it return the information of the source database of the destination database?
Get-Mailbox will return whatever mailbox instance that the target identity is currently linked to.
Once you submit a move request, two instances of the mailbox exist, but the account that owns the mailbox will still be linked to the original.
Once the move has been completed, Exchange will re-link the user identity to the new instance of the mailbox, and you should see that the
Database property of the mailbox returned has changed to the name of the database that you moved it too.