A while ago, you would easily fall to your death, even on not so steep slopes, such as the stairs in hydlaa. When that was changed, you would just get stuck on anything steep. More recently, this was changed again to let you slightly move in places where you would previously get stuck (and /unstick did not help, as you were in a steep slope). Unfortunately there were some errors in computing vertical movement, which result in you getting damaged anyway. I cannot find the bug report right away, but I know that several things are fixed for this, and should be available in the next release.