Hi, the Wild preset used in your scene is not the same included with Forest, it has been modified: max file is "_fp_mental_wild_grass_field01.max", which doesn't exist in our library, and the material is a multi-sub with 20 materials, while the library has only 4.
Not sure what is causing the shadows issue, but i tried to reapply the preset from library and it renders correctly. Probably there is some problem with materials.
Please, do this:
1) Delete the Forest object.
2) Delete the objects "_library_5JUPFDQ__fp_wild_grass_01_clump_01", 02 and 03 from the "forest_templates" layer.
3) Create a new Forest, selecting the Wild grass preset from the library, and enable Edge mode.
That should solve the problem.