Hi Dave. I've narrowed down the issue but it makes absolutely no sense.
The category module drills down and filters correctly under the following circumstances:
1. It's on the same page as the BuyNow module.
2. In the category module settings the buynow page is "NOT" selected and left blank.
This is how it's setup on your test website.. the BuyNow page isn't selected, yet it is the same page anyway. So I went to my website... went to the buynow module page.. went into the category settings.. UN-selected the buynow page.. and it works fantastic. As soon as I select the BuyNow page it doesn't work and all products show no matter what is clicked on.
I still have a problem on the home page.. I have the category module on the home page which is absolutely necessary for design purposes and I can't get it to work.
Thanks,
Patrick