Resting in the tutorial cave tent seems to have fixed it.
But yeah, The area outside of the vision cone was pitch black.
Viewing post in Latex Island - Public Demo comments
I don't really remember exactly what I was doing.
I know I was wandering through the map, Then rested at some building on the eastern half, And found everything to be dark afterwards.
I apologize for the lack of info. I do happen to have a single, Somewhat isolated (The save I made before it is 45 minutes older) save, If that could help.