The administration and maintenance of Microsoft Exchange Server to ensure secure, reliable, and efficient email and collaboration services across an organization.
As a follow up I ended up contacting Microsoft on this issue. To resolve the issue we suspended database copy and resumed it. That seems have fixed it for now but I am continuing to monitor.
The 2 errors I was getting after running:
Get-MailboxDatabaseCopyStatus * | ft Name,Status,CopyQueuelength,ContentIndexState,IncomingLogCopyingNetwork -AutoSize
Were:
{Exchange1,MapiDagNetwork,An error occurred while communicating with server 'Exchange1'. Error: The requested address is not valid in its context}
and:
{Exchange1,MapiDagNetwork,An error occurred while communicating with server 'Exchange1'. Error: Unable to write data to the transport connection: An established connection was aborted by the software in your host machine.}
we ran:
Suspend-MailboxDatabaseCopy MailDB01\Exchange3
Resume-MailboxDatabaseCopy MailDB01\Exchange3
Hopefully that helps someone else with considerable less headaches.