The building in the screenshot appears to not have a "collision plane" on the outside edge. So when you move against it, you clip through the mass of the wall and can see through to the other side.

The floor there is slightly elevated I think, so I'm not sure if you can move through the wall as I was stopped at the inside edge of the wall. I did not think of trying to shoot while in the wall to see if it goes all the way through.