When the camera pans around behind a wall, the wall itself fades away visually but not physically. Trying to click anywhere to move the characters while the camera is behind a wall results in the character running to the wall. Also, some walls don't fade at all. Specifically in the very first room when you get control of your character, if you walk toward the camera without rotating it, it just moves behind the wall and all you can see is the back side of the wall. I ran into this a few times during the opening area on the Nautiloid with a few different walls and objects.
