Masonry Element Showing Too Much

I’ve need to show Posts in groups.
I’ve got Post Categories and the Posts are assigned to their appropriate Category.
Some Post Categories, however, have no Posts assigned to them for now and may not from time to time. (Like Special Deals or Rebates)
I’ve got a Page for each Post Category and placed the Masonry element into it.
The Masonry Content tab is set to the matching Post Category.
I’ve got Sortable set to NO.

So, my problem is this:
The Pages for Post Categories that have Posts work as expected – they only show the posts from their assigned category. This is great.
HOWEVER, When I open a Page for a Post Category that does not have a Post, all Posts are showing. I thought it would be empty. I need it to be empty until a post is assigned to the Post Category it is supposed to reflect. How do I fix this?

Thanks!