Assume that you use Microsoft SQL Server 2016. During distributed availability groups (DAG) creation, when you query sys.dm_hadr_availability_replica_states, access violation occurs.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
The issue is fixed in the following cumulative update for SQL Server:
About cumulative updates for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server: