Light Bleeding and Mystery Light

Hello every one. I know these questions most likely been asked many times over but I hope to get some type of response. I have two problems really. First off, One of my walls (at the floor of course) is bleeding and have no idea how to solve this one. At this one, I have the wall and floor both sitting at X-0, Y-0 and Z-0 so I thought I may have no problem with it. I have tried moving the wall a tad in any one direction by a smidgen such as 0.1 or so to see if it helps and not help. I have attached a few photos of this below. Also on this same photo, is a light shining on the Stairs across the room that is bleeding through the corner of the same area as the light on the floor. No light can be seen passing through the wall or corner any place. Next, the Mystery light that is shining so bright on the wall. This one looks like a light bleeding between the wall and a door. Nope, no door or corner here. I have tried searching for many hours to locate this one and yet to locate what it causing it. I will post a photo of this below as well. Thanks in advance.

For the sliver of light on the floor, there might be a mesh that’s one-sided that isn’t blocking some light. In other cases, make sure you don’t have surfaces that go beyond the edges of the wall and are visible to light outside, that can cause light to bleed onto the interior, it can help to have an exterior surface to block light from coming in where it shouldn’t.

Thanks for the quick reply. I did think of what you have stated and do not see this case. All my walls and floors are placed either by Snapping 50 or 100 so there are no overlaps as far as I know of. I do also have an exterior surface placed for the exterior part of the building as when it is to be placed on some landscape and such. For each room I am making, I am using different maps using Different Level Streaming Volumes. There is not much info online that talks about using that, but I am trying all the same. Any other suggestions or tips be great here. Thanks again.