Crosshatch/Sketchy shadows but NOT as post process?

I am trying to create crosshatch shadows but not as a post process, following this blog post Disney’s Dr. Facilier shadow effect in Unreal Engine 4 – Tom Looman but I am getting weird results.

I have forward rendering enabled and the material “works”, sometimes. Imgur: The magic of the Internet

I am basically wondering if there’s an alternative way of generating material’s lighting map, or if someone knows why am I getting these weird “bugs” when using this method.