This happened to me a while ago, but i noticed it has not been patched yet. In fractals, when doing the volcano instance, after my team forced the shaman to jump into the lava, we encountered a vampire bat. The team proceeded to kill the bat, but the bat flew into the wall in the left. Unwittingly, we all followed suit, and discovered we could go through the wall. Unfortunately for us, it was a trap. All 5 team members fell into a ditch that was inside this wall, and since we were stuck (fractals have no waypoints) we were forced to restart the whole fractal. Just want the developers to know and fix this for any people who have the bad luck of encountering this problem and having to start over again.