Do not want. On first glance it looks nice, but can't you folks see the halos around the pillars? It looks like the same sort of effect you get when running one of those fourier algorithms for deblurring images.
Actually, it's a cheap alternative to radiosity and widely used way before its realtime implementation. Simply put, the algorithm darkens the areas of the object surrounded by other geometry.
The artifact you mention depends on leadwerk's current implementation.
Probably the most useful shader you can have to enhanche your scene in conjunction with realtime lights (they replace the need for lightmaps altogether).