Function works in parameter mode, but not in preview mode

I'm trying to use functions in the 2D transform node to allow users to rotate, uniformally scale and change horizontal vertical tiling of the opacity map. I have a value processor node connected to the 2D transform node that handles the rotation and scale. The 2D transform node's tiling mode is linked to an input paramter I've created.

Everything works perfectly when I use my default parameters, but when I go to the preview tab the H & V Tiling input has no effect. The rest of the functions work as expected. Any help would be appreciated.