Not entirely sure if this was fixed yet, but in the City of Abominations, at the slope with an arrow by the right wall (when running up) I always experience a "rubber band" glitch and it's quite hard to get to the top of that slope and continue onward due to this. Also this isn't an "every once in a while thing" but every time I went up that small slope. If it's not fixed and the location isn't known, just ask and I'll go back and find exactly where it was (since I haven't been in the City of Abominations for a few weeks).