It's probably been mentioned to the right people, but since I haven't seen it...
DTV Grunwalder CastleThere is an invisible barrier placed here:
Probably a 2m or 4m barrier. I put one in for context's sake.
***EDIT***
I've just seen a major exploitation. Dunno how yet, but I have an idea. I'm bound to get some hatin' for this report.
I think that random barrier I first mentioned, and how the players got down there are related.
***EDIT***
The two problems are not related at all after looking at the scene file. The first is just an oversized barrier that is reaching too far out and down. As for the second, while I've seen the general place where the glitch is performed, I have no idea how it works. Frankly, it shouldn't, but just moving the barrier forward a little will probably fix it as there will be no place to glitch out there.
Speaking of glitching, same map, different barrier problem. Down the stairs and to the right of where you spawn, at the walls you can get stuck because, again, oversized barriers are placed for the top of the walls' walkways, and it reaches down to the bottom, trapping players who inadvertently back into the indentations in the walls. (Sorry, no pic.)