Issue with the users home server

Hello,

get-mailboxdatabase "db1" | get-mailbox

shows all the users which are in that db1 mailbox database. However, the "Servername" is wrong for the majority of the users. Previously that environment had 2 exchange servers in DAG. At some point in time, DAG config and the environment got completely corrupt, the end result, out of 2 Exchange servers, MBX1 and MBX2, MBX2 survived and running all the databases. However as a result of the previous problems, the output of the above command points 90% of the users are located on MBX1, whereas 10% on MBX2. All of them are located on DB1.

I would like to fix the situation, for this I have installed new Exchange 2013 server, planning on moving all the mailboxes to the new server, format the other one and recreate, thus creating clean DAG config. However I can't migrate mailboxes to the new server, getting error: "StalledDueToReadUnknown" , which probably corresponds to the described situation.

Any suggestions as to how to proceed and resolve the issue? I don't really like the idea exporting everyone to PST and import them all to the new DB.  Perhaps there's a more elegant solution? 

When running "get-mailbox user | ft" for one of the problematic users, I see that the below values are pointing to the old server

Perhaps there are more attributes to fix?

Thanks.

Memento Mori