Symptoms
Assume that you use Microsoft SQL Server 2012 Analysis Services (SSAS 2012) or SQL Server 2014 Analysis Services (SSAS 2014). When you create a calculated member at the ALL member level in a dimension hierarchy, the Except function does not return this member in a query.
Resolution
The issue was first fixed in the following cumulative update of SQL Server.
Cumulative Update 4 for SQL Server 2014 /en-us/help/2999197
Cumulative Update 2 for SQL Server 2012 SP2 /en-us/help/2983175
About 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:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.