Nope, this is an asset based problem. If you can find a bad one, I will check it out, but I need to know package name and mesh name. 
PS: You shouldn’t need to fiddle with the lights as long as you’re using the default level.
I’m running into the same issue with seemingly all the grasses in this package. See screenshot to identify one in particular
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I had to reinstall this to take a look, because I had removed it. I do recall not being happy with this grass.
It was too light, and too high poly for me, although it looks ok now.
Again, with this one, the brightness in the MI is the answer:
( Yes, I have it on 1, I know, but I definitely have had problems with the group of meshes ).
I have spent a lot of time looking for good grass meshes. This is pretty good:
But it’s really a material, and you can apply it to any grass mesh. There is a well made grass mesh in the pack.
In summary, as you can see from the other meshes, this is an asset / material problem really. Hope you got some answers.
Thanks so much for all your efforts, lots of learning for me. Thanks for the link, will check it out and plat some more with MI