Shrubbery gets darker when I move

Hi anyone and everyone.

Recently I noticed that whenever I move the surrounding bushes and map gets darker. Its even worse on night maps.

I have the usual comp settings that most people run.

Got an xt 7900 gpu and 5800 something amd cpu ( in a bit of a rush so im leaving it at that for now)

If anyone has had this issue before and resolved it I'd love to know how :)

Thanks