Assume that you use the CONTEXT_INFO system function in SQL Server 2014 or 2016. When you assign a hexadecimal value that ends with trailing zeros to context_info, every combination of two trailing zeros ('00') is truncated. Therefore, when you retrieve the context_info value by using the CONTEXT_INFO function, wrong values are returned.
The issue was fixed in the following cumulative updates of 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. We recommend that you download and install the latest cumulative updates for SQL Server:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.