I have the same problem as this person back in 2021, where ambient occlusion being enabled breaks the lighting on surfaces. Does anyone playing the game on Linux have working lighting with this setting enabled? Could you share the distribution and specs of your system? I'd like to do some debugging and hopefully figure out the cause of this issue, but I'm not sure where to start.
For what it's worth, I am on Arch Linux with integrated AMD graphics, and the lighting is broken for me.