after the bridge battle, I thoroughly investigated every inch of the screen. I was checking for hidden passageways through the trees on the right, and I accidentally went to the next zone with the wagon guy. I glitched into the outside walls of the map (in the trees, pond, etc.) and I had to save and exit to fix it. Guessing it's from the mechanic where moving forward on a slanted thing moves you down the slant, thus allowing that to happen.