Dynamic Range, Time Property Filter = Empty Matrix - A bug?

I think I've found a bug in the way the Excel Add-In generates MDX under certain 'rolling' conditions.  The requirement I have is to be able to forecast at the day level for a rolling 6 months; starting from the current period (which is to be updated each week) running for a period of 180 days (~ 6 months)

To prevent requiring 180 columns, a dimension property based filter must be available to select the month in which to forecast.  This will provide a more concise data entry form detailing up to 31 days of the selected month in which to add forecast values.