Bug 783.858.862: Act 2 town does not go dark anymore

I'm in the act 2 town "The Forest Encampment". I marked the quest status on the right, you can tell I activated the sphere in the vaal pyramid already so the darkness should have fallen. They are speaking their text like "Nothing like this happened before you arrive" and such. But the graphics does not turn dark. Losing a bit of context like that.