SSAS 2008 Bug: Normal Additive Measures and Semi Additive Measures in the Same Measure Group Don't Display Properly

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.