Foliage gets darker when camera goes farther away

I have a single material for two different planes of grass.
One is slightly rotated, the other is not. However, when zooming farther away from the grass, the ones that aren’t rotated at all get darker. The ones that are slightly rotated do not change color at all.

Here is a gif that showcases the behavior:

It’s a two sided shading model with two sided enabled, the base color is plugged into subsurface color as well. They do not cast any shadows.
So how come that the color of the not rotated ones gets darker? Does anyone have some experience with this?