Foilage shadows issue?

The scene uses stationary sun and sky so I can’t use distandce field ao. Switched to distance field ao by using movable skylight. Did not work.
Here is how it looks with a bigger scale:

EDIT: [USER=“3140864”]MostHost LA[/USER] Seems the vertex normals were the issue. It is fixed now. Thank… Now I am having this issue:

Dark patches that move around the grass foilage in a wierd manner. Any idea what might be causing this?