Raytracing Shadow missing

Raytracing is an amazing new tool, but I am having issues with getting shadows on Grass Types for my landscape. Essentially I am using the GrassType to distribute rocks in my environment. In my original setup I have shadows, but with raytracing, there are only shadows on non GrassType rocks. I added an example image of two rocks the left one being generated by the landscape, the right one being placed manually to match the other rock.