In this one area of my map I have the auto-generated grass sprites very dark - basically black. not exactly sure why this happened. The area is pretty lit by the skybox above it. I had a theory that since there were 0 other lights in the scene, that somehow contributed. I was incorrect. It's only in that area though. In a different area they are normal same texture used, different places in the map, enclosed by different brushes and skybox brushes.