I'm not sure this is the same thing. These lines are visible at all times of day, they seem to be only based on physical position. I loaded up my game to double-check just now, it's 22:04 in-game and they're still visible. One of them you should be able to see by looking at the main window while going up and down the short stairs in front of the base entrance, with a good view of it if you stop around where the bottom stair meets the ground. It looks like some sort of weird reflection artifact.