BUMP! @seandennis: you’re no n00b, many peeps are having this and similar Dynamic Lighting issues. As fighter said it’s a known bug.
So, EPIC, when is this going to be fixed. It’s 2017 and Dynamic Lighting still broken (i’ve not tried for a few months now)?
I’m having the exact same issue and i believe that “thin” roofing is not to blame (or not entirely) and here’s why: the Devs of a game i’m also modding for have made at least one building with a single polygon(dbl sided) for the ceiling-rooftop, and although this appears to leak light at some edges inside the building in the editor, when “played” there is no leaking and no errors with lighting related to the single polygon plane of the roof and no wierd selective lighting errors such as that above (admitedly it does have a floor below it. You may also notice Normals being lit whilst the “Sun” is below the horizon - play with sun-angle and see what happens, the lighting is quite bizarre and also quite obviously broken to pieces.
Making walls and roofs/cielings stupidly thick to compensate for broken lighting is not the answer.
Telling us to simply add Blocking objects/planes to block light is also not the answer.
Fiddling with a bunch of settings that don’t actually help the situation is also not the answer.
fixing the (Dynamic) lighting system so that backface culling is ignored (pray, remove it entirely) at least on Terrain, or any “Ground-Plane” labelled/type of object, will help, i’m sure.
Please EPIC, do something, this is getting sad - I am probably going to give up with modding full-stop as UE4 has really made it difficult to go forward with my, fairly simple, project.
CryEngine has had realtime dynamic lighting for ages - i’ve used it and it is pretty good - what’s stopping you (EPIC) ?