Game Mechanics: Going "unconscious" above 0% health

[Ciroco]

This hasn't happened to me at higher levels, but it happened twice within a few hours on a low level character: I have collapsed on the ground between 1% and 5% health and been unable to move or cast spells. There is no "You have been knocked unconscious!" message, but a third party view shows the character lying on the ground. When the character is finally slain, the unconscious and slain text occur simultaneously.