Symptoms
You may receive time-out errors when you use SQL Server 2016 AlwaysOn Availability Groups. Additionally, you receive error messages on a sync secondary that resemble the following in the SQL Server error log:
Always On Availability Groups transport has detected a missing log block for availability database "database_name". LSN of last applied log block is (LSN_ID). Log scan will be restarted to fix the issue. This is an informational message only. No user action is required.
Resolution
The fix for this issue is included in the following cumulative update 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:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology Microsoft uses to describe software updates.