Bad geometry and collision in "Back Hall"

[Mikezila]

In the room with the fountain, called "Back Hall", there is some z-sorting issues under the overhang, along the back wall. Facing away from the fountain, the right staircase has no collision on it's back or side. It's possible to walk through the wall and the side of the staircase.

Sorry if there is already mention of this, but I'm avoiding reading too much for fear of accidental spoilers.