yeah thats a known bug, it has nothing to do with the wall itself, but the game doesnt realise you hit mud/void/however you want to call it until 1 frame after you actually hit it, so you can dash/jump in that frame where the game doesnt realise yet, so you dash. This is a very hard trick, because and its a frame-perfect and the framerate is uncapped, so the framerate changes all the time.