Consider the following scenario:
You enable Microsoft SQL Server Service Broker (SSB) in SQL Server AlwaysOn Group database.
You shut down and restart the database.
Make sure that the Acknowledge (ACK) is received successfully.
In this scenario, message is not removed from transmission queue even though the ACK is received successfully.
The issue occurs because, when you start the database after the clean shut down, SQL Server does not check whether the transmission queue deferred delete task is reusable. It assumes that the transmission queue deferred delete task is ok.
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:
To work around the issue, failover the SQL Server Availability Group to the secondary replica (and failback if it is required).
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.