Sometimes when I'm prone, I'll give my character a command and he decides that he has an overwhelming need to roll to the side. Either side, it seems, and at random times that I'm unable to reproduce on purpose. When I have my character prone, leave him still for an indeterminate amount of time, and then give him a command such as to move or get up, he'll occasionally just... roll. He has repeatedly nearly rolled off of several buildings while I was near the edge of their roofs, and it seems that the time it takes for him to decide to roll on his own is inconsistent. Once, I was sitting still for a while and keeping watch over one of my friends and rolled after 20 minutes, and another time I was simply laying down to check my inventory before getting up after a few seconds to instead nearly roll to my death.