My GPU Lightmass bake has extremely dark terrain. Works fine on the static meshes around the level, but the terrain itself is very dark in comparison. Why? Seems like a bug. Also has random block box spots around for areas that seem to have not rendered. r.PathTracing.LightGridMaxCount 9999 fixes some of hte objects but not all.
Its not just terrain… other bugs in lighting bakes as well when comparing full bake vs bake what u see modes.