Devin Knight and I stumbled onto another weird SSAS bug today. We had a measure group that had two measures. The first measure was semi additive (Last Non Empty) and the second measure was a normal additive type (Sum). The additive measure would not display along side the semi additive measure, whether I browsed the cube in Excel, BIDS, SSMS, or wrote an MDX query.
Well as it turns out this is a known issue that was identified some time ago. SQL Server 2008 SP1 solves this issue: http://support.microsoft.com/kb/969099 .
So if you’re ever on site working in an environment you are unfamiliar with and you experience goofy behavior where semi additive and additive measures in the same measure group do not display properly, check the SQL Server AS version! The version to look out for is 10.0.1600.