Exchange 2013: Database copy has been blocked from automatic activation on server by an administrative action. Reason: None specified.

After updating two Exchange 2013 mailbox servers in a DAG environment to CU8 and running Test-Replicationhealth, Database Availability reported an error:

I tried to use -autosize to show the entire error which wouldn't work, but after googling around I found this:

 $r = Test-ReplicationHealth  
 $r | ?{$_.Result.Value -ne 'Passed'} | fl  

The entire error is as follows: Database copy 'DB01' has been blocked from automatic activation on server 'EXCH2' by an administrative action. Reason: None specified..

Its actually an easy fix, go into the ECP, Servers -> databases, suspend the passive healthy DB, wait a moment then Resume it.

Now test-replicationhealth again and you should be good.