Why is my DirectionalLight leaking through BSP?

Hello everybody,

I have been searching the forums for a few days now and still have not found a with a solution. I have a DirectionalLight in my level for the outside sections with all settings set to default. I have an interior section that should be completely blocking out all exterior sunlight (ie the DirectionalLight). However, every time I build the lighting I get splotches of light inside my room that should only be lit by the PointLights inside I have no holes in my blocked out room (made entirely from BSP, I have messed with different lightmap resolutions on the BSP ranging from 16 to 2048, enabled and disabled two sided lighting, made the walls thicker and thinner, and put layer upon layer of BSP shells around my room (a room inside a room inside a room dawg). Nothing seems to do the trick of keeping out the light.

I originally had a single additive BSP with a subtractive BSP inside to make the room. I’ve deleted all that and just made all six sides of the room independent of each other (6 separate BSPs). Neither of these tactics have returned any love to my poor soul.

Here’s what I’m talking about:

Does anyone have any tricks I haven’t tried yet or am I missing some important central concept of lighting in UE4 that will make me feel silly when I finally figure it out? Any insight at all would be appreciated.

Thanks everybody!