Symptoms
If DTC support for an Availability Group is toggled between PER_DB and NONE multiple times, some internal fields in SQL Server may not be reset correctly. In this situation, SQL Server will continue to work as expected. However, when the Availability Group is failed over, SQL Server may generate lots of dumps, and the failover may get stuck.
Workaround
To work around this issue, you can force kill the SQL Server session that hosts the old primary database of the Availability Group to finish the failover.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Resolution
This issue is fixed in the following cumulative updates 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:
References
Learn about the terminology that Microsoft uses to describe software updates.
