Assume that you set up a database mirroring session in SQL Server 2012,2014 or 2016. You add a witness to support automatic failover. In a rare situation, the mirroring session may stop, and then the data is no longer synchronized. Additionally, an automatic failover doesn’t occur as expected.
This issue is fixed in the following 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: