Rendering is only half lit correctly / clear deviding line between black and lit objects

Hello,
I have the problem that half of my rendering is correctly lit, the other half is not. It is a slow camera rotation and as you can see in the images, there is a clear separation between light and dark. The problem affects not only the rocks in the foreground, but also the objects in the background. However, this is less noticeable because of the atmosphere.

I have a hunch that it is related to the console variable r.ScreenPercentage. I currently have this set to 200, but the problem also exists with lower numbers, except that the dividing line between light and dark shifts to the right. Without this variable, the problem does not seem to exist.

I have to mention that this is only a section of my scene. The entire resolution is 6000x768px. Unfortunately, this is necessary because the animation has to run across several LED screens that have exactly this resolution.

I would be grateful for any tips.