November 2017 - last edited February 2018
Product: The Sims 4
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What expansions, game packs, and stuff packs do you have installed? All
Steps: How can we find the bug ourselves? 1st Case: Draw a room and place a ceiling light within it. Add a door to the exterior that has minimal windows (I used the Unbranded Entry Device). Advance time to night. 2nd Case: Using the original room, draw a second room adjacent to it. Place an arch or other windowed door between the rooms (I used the same Unbranded Entry Device door). Keep time at night (easier to see the effect).
What happens when the bug occurs? 1st Case: Light forms in a strong semi-circle around the exterior door. It is extremely bright and takes up a large area when compared to the tiny panes of glass on the door. The same problem exists with windows, which you can test by selecting windows, that in theory shouldn't be transferring much light (like the Holey Geometry stained glass window). Note that as you raise a window up higher on the wall, the exterior lighting effect diminishes, so proximity to the ground may be a large part of this issue. 2nd Case: Light spills over very strongly into the adjacent room, making the side walls especially bright.
What do you expect to see? 1st Case: See second image below where I have knocked out one tile of wall where the door had been. Note the more natural flow of light from the interior. I would expect to see an effect more like this when the door is in place (although much more muted because most of the door is solid). 2nd Case: See fourth image below where I have knocked out one tile of the wall where the door was. Note the more natural flow of light from the first room to the second room. I would expect to see an effect more like this when the door is in place (although again, much more muted, since the door's windows are so small).
Have you installed any customization with the game, e.g. Custom Content or Mods? Never used.
Did this issue appear after a specific patch or change you made to your system? No
Here is an image of the lighting flow to the exterior as discussed above:
And here is an image of the more natural flow of light (other than the weird corner bits) when the wall tile is simply removed:
Here is an image of the lighting flow to the interior as discussed above:
And here is an image of the more natural flow of light when the tile of wall is removed: