Assume that you use Microsoft SQL Server 2012 or 2014 Always On Availability Groups. When you try to drop a database that's part of an availability group, you receive the expected error message 3752. After that occurs, the transaction log redo thread at the secondary may stop until you restart the database. Or, it may suspend and resume data movement for this Availability Group.
Cumulative Update Information for SQL Server:
This problem is fixed in the following cumulative updates for SQL Server:
Service Pack Information for SQL Server 2012
This issue is fixed in the following service pack for SQL Server:
For more information about how to obtain the latest service pack, see How to obtain the latest service pack for SQL Server 2012
About Service packs for SQL Server
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.