County Layer that uses Set Analysis displays counties with 0 counts

[LJR]

I have a Map that has a State layer, County layer and Zip Code layer that the user can zoom in an out of. I am using the same measure calculation for all layers. In the State and Zip Code layers, I never get a State or Zip Code with a count of 0.  Only values of 1 or greater or displayed.  However, on the County layer I get counties with 0 counts displayed in my map.

My measurement calculation is: Count({<Year={$(=$(vSnapshotYear))}>}[Case ID])

I have a variable for the user to select a year. My users really want a drop down for the year instead of a Filter Panel. 

When I use the Filter Panel to select the year, and use measure calculation of Count ([Case ID]) only counties with counts > 0 display.

Why is my year variable not working on the county layer for my map? Here are my setting for the County layer