Beware Hidden Calculated Members

Here is another one of those "by design" issues (see the Not All Calculated Members Are Born Equal blog for another recent gotcha) that are not documented but can sure waste you precious time figuring out. The issue was first submitted on connect.microsoft.com by Greg Galloway almost a year ago where it was left in an investigation phase (what can we do to get the SSAS team actually review the connect cases and post findings?). Then, I submitted a similar issue and official support case since I was 100% sure it was a bug and I needed a closure. Alas, Microsoft came back to declare it "by design":

"…per feedback from several AS 2005 Beta customers, for compatibility with pre-existing AS 2000 behavior, AS 2005 RTM (and later releases) was changed to not include hidden calculated members in cell calculations and scopes (except when a hidden calculated member is explicitly referenced in the calculation scope)."