fyi - all but one of my SGs were failing SCR replication with the following:
The Microsoft Exchange Replication Service encountered an error while inspecting the logs and database for EX1BAa_l on startup. The specific error code returned is: Microsoft.Exchange.Cluster.Replay.FileCheckLogfileMissingException: File check failed : Logfile 'D:exchsrvrMailboxBAa_lE0200000001.log' was not found.
at Microsoft.Exchange.Cluster.Replay.FileChecker.CheckLogfiles(Int64 minimumGeneration, Int64 maximumGeneration)
at Microsoft.Exchange.Cluster.Replay.FileChecker.RunChecks()
at Microsoft.Exchange.Cluster.Replay.ReplicaInstance.ConfigurationChecker(Object stateIgnored).
I noticed that the one that was working was the only SG that did not have an underscore in the name, so I created a couple more SGs without underscores in the name and moved mailboxes over to them - they are also working fine. Is it possible that SCR replication breaks when underscores are in the name of the SG? My DBs had no underscores, but dashes instead (which I removed when creating the new ones).