Depending on how close you are to a ledge or whether you hit a direction after falling through them it may not work properly. If you're too close to a ledge you will slide towards the ledge, and if you hit a direction immediately after you fall through a set of stairs you will land on top of them.
Occurrence - Every time I've attempted the above Severity - Mostly annoying
I've also had instances where I'm about 1/4 the way down a set of stairs, attempt to fall through, only to get a slide. I'm not entirely sure