Shadows look like they painted on top of the meshes instead of being occluded. Stationary sun and skylight, only on forward rendering, only with instanced foliage.
Reproduceable, here’s the clean project I reproduced this in: https://drive.google.com/open?id=0B6eHVMAAL_KNUFN5a09kS0ZseHc
Forward Rendering in 4.13 is still very experimental and isn’t fully functional yet. So there are bound to be some things that will have issues or will change significantly before being announced with 4.14 as a more rounded feature.
With that being said, you can select the foliage and enable the option for Use As Occluder in the Foliage Tool for the specific asset.
I hope this helps.
Thank you, Tim, that’s exactly the thing I was looking for!