The "dark cockpits" issue, is a known Laminar's bug which will be fixed some time in the (near?) future. Some aircraft with small windows and dark textures suffer from that the most, like the DC3.
I have created a FlyWithLua script, that hacks X-Plane to fight this, as a short-term solution. I'm attaching it here to give it a try. To install it, drop it into X-Plane12/Resources/plugins/FlyWithLua/Scripts folder.
I'm waiting to get 12.1.0 in my hands to see what might will be changed, and see if I can include a more permanent solution into 2.0.4 update.
bright_cockpit.lua