Replicating an engine with SQL Server AG virtual database
Engine replication is the same for the SQL Server AG virtual database as other SQL Server virtual databases. However, for replication to work for the SQL Server AG virtual database, the user needs to make sure that the SQL Server AG virtual database exists on the source engine.
Best practices for Engine replication with SQL Server AG virtual database
Verify that the primary replica of the SQL Server AG and the primary replica currently shown in the SQL Server AG virtual database runtime attributes match.
Make sure that the correct synchronization state of all the replicas is available under the SQL Server AG VDB replica time flows.
Make sure that either the SQL Server AG virtual database has been disabled on the source engine or in the event the source engine is not available, the underlying database of the SQL Server AG virtual database has been manually cleaned up on the target cluster before an Enable operation is attempted for the AG virtual database on target replication engine.