Why is Foliage not affected by RayTracing GI?

Hi guys,

I have the following problem. I habe some expirience in working with unreal, but mainly on projects that involve interior renderings and architecture and have little experience with foliage. I am currently working on an architectural project that has to have some foliage. For the rendering, I usually use raytracing GI, reflections and all. When I started to put the trees in my scenes I came to the problem that my trees do not receive any raytracing GI and the leafes are completely dark on the bottomside. Here are some screenshots of a simple scene that I made, that show the whole problem better. I made two screenshots with different skylight intensity and you can see that the room on the left gets brighter, however the trees stay dark. Also on the right of the screenshots you can see my post process volume raytracing settings.

Thanks for the help in advance and have a nice day!