Excel 2013

I have a slicer of vendor names connected to a pivot table, and I use the

=CUBESET("ThisWorkbookDataModel",Slicer_Vendor_Name,"Vendor Name")

format to return the slicer selections. There are 6 slicers going against this particular pivot table (if that matters). I'm using the CUBESET function in part of a named range to return top 10 values in MDX elsewhere on the sheet.

All other slicers and related CUBESET functions are behaving as expected. For the vendor slicer however I'm getting #N/A in the CUBESET function when I unselect a vendor name in the list (i.e. all vendors but one are selected). Selecting all vendors, one vendor, or multiple vendors (when starting with only one) works, but unselecting one or more vendors when all vendors were selected at the start causes the #N/A. None of the other slicers are displaying this behavior, and they're all returning values from the same table or higher in the data model hierarchy. Very weird.