There is a part of the map where you can walk on thin air, as if there was a stair above you. In the map you can see that is passable terrain, but the terrain hit box treat it like it is the same elevation of that stair on the right.
Place where you can climb on air.
Location on the map.
Edit:
I found another spot in the same map where you cam climb in air from the bottom part to the top part of a cliff, this one is smaller than the first.
