Hey , thank you for the reply 
Stationary light itself isn’t lightmapped, the lighting is still dynamic. Only indirect lighting contributed by this light is in the lightmaps. In other words, for this light UseDirectLightmap=false
And this is what docs say about light functions: “Also, Static Lights cannot not use Light Functions, as this feature is only available for non-lightmapped lights, like Stationary and Movable lights.”. Changing light mobility to movable doesn’t do anything, since stationary light is still “almost” movable
I didn’t modify exposure settings in a post-process volume, they’re default. And turning it off darkens the room completely, since this is a night setting, it’s an expected result
The problem is how light functions work, light intensity is masked in the world by the light function, while the actual intensity value is still present, and subsurface materials uses this. As i said earlier, that’s not an actual bug, it’s more of a feature request
Thank you!