Shading on Foliage issue_Way too dark under shade

Hi guys, Im doing the landscape environment. The grass I used was based on [this][1]. What I got was quite acceptable but the grass area under shade was completely black as if there was no light. I’ve searched on forum and answer hub and found numerous causes for that one but seems like no solution worked. The closest issue was [this][2] but normal map is not the answer. The skylight intensity has no impact on foliage, the lightsource is stationary (dont want to change to movable since I have static meshes), foliage is movable and cast only dynamic shadow, and material is 2-side, had vertex color on AO, texture on subsurface like the link, replacing with other grasses in Kitedemote does not work either. Does anyone has any idea what I am missing??? Thanks in advance.