Hi.
I have a strange foliage bug on my landscape. Groups of grass instances are changing brightness, when I move camera. This video shows bug:
?v=scKly5NbkSY
Grass near the road become darker or brighter.
Engine scalability settings are all Epic. Other settings and material:
What happens when you disable the “eye adaption”? -> in the post process volume under auto exposure 
+ place some meshes by hand and then check if your problem still appears
I disabled all posteffects, and it doesn’t solve problem. But I solved problem in another way.
When I uncheck Cast Dynamic Shadow on the grass instance in foliage window, this visual bug disappears. But the foliage don’t cast shadows! It’s not a big problem with grass, but when trees don’t cast shadows, it looks ugly.
I also got this message:
Large actor? It’s only 300 instances. I’m going to cover all level with the grass and trees and I want them to cast shadows (maybe not grass but trees any way). How can I fix it?
Detailed bug description:
You can see it in the video from Editor.
?v=PxIm-uSUqeE
How to fix it?
On your lights, such as directional light, check static instead of stationary/movable, which make it dynamic. If you need the sun to change directions then that might be an issue. A quick fix for the time being I suppose. Then I look at the time stamp of this post, and it’s been 4 years hahaa. I hope you ended up finding your solution.
Try disconnecting the emissive color. The behavior though looks like a LOD kicking in so I would look at the mesh to see how many levels it has. It’s typical to LOD a material to decrease the level of shader complexity so the behavior looks like the emissive kicking in and out.
