Hunger in the dark map. A chaos spawn managed to grab me, slammed me around, and when he was done, he threw me right through the nearest wall. I survived and was able to stroll around for a bit, even attack and kill the enemies inside the map, but couldnt get back in. Eventually I fell off an invisible cliff and died.
How frequent? - Only this once so far.
How to reproduce? - I guess have a Chaos spawn grab you in one of the narrow tunnels and see where that takes you.
It´s not a big issue, but you might want to have a look at the map layout in the more narrow tunnels, or more generally, how level boundaries interact with the player model when thrown by a chaos spawn.