Too many cleanup retries, giving up when migrating mailboxes from 2010 to 2013

I am migrating mailboxes from Exchange 2010 to Exchange 2013. 

I migrated a few test mailboxes, in a batch which worked fine. I then migrated a batch of two old mailboxes that are active but not really used and they worked fine.  I then migrated my mailbox and another IT users in separate batches and the migration completed with errors. The error is as follows:

"Warning: Failed to set RehomeRequest on some of the requests related to the mailbox after the move. Error details: Too many cleanup retries, giving up."

I followed the advice here and the same thing still happens:

https://social.technet.microsoft.com/Forums/office/en-US/8898e822-c371-4dd2-9814-6c1fea5c6305/failed-to-set-rehomerequest-too-many-cleanup-retries?forum=exchangesvrdeploy

I am using the same account that worked on the previous batches.

Any advice?