Light Fragments in the shadows of one sided Meshes from Quixel.

Hello Everyone!
THese Fragments do not happen with Meshes that have texture all around, but with Meshes that have the Texture on one side and when the DirectionalLight shines throught the side where there is no texture.
Setup: Stationary Directional Light (Atmosphere SUN Light is ON ), SkyAtmosphere, skylight and exponentialHeightFog.
Those Ligh Fragments also only seem to apear on halfsided meshes, but not on the player, but the player also casts shadows onto these light fragments.
I also checked “use Two sided Lightning” on the half sided meshes.
Does Anyone have an Idea where the Problem lies?

Jonathan.Holmes Hello Jonathan! Thank You! Most of the light problems are gone now, even without Two sided Lightning.
But, there are still some light Fragments on the one sided mesh even with a Box between it and the sun. Do you have any idea, why those are still there?