There a quite a few small problems with rocks and rocky terrain in the game. sometimes there are groups rocks that are only at feet height that can trap you if you venture into them.

And some rocky cliffs that are seemingly flat on top trap you and you have to use the V button constantly to get out of them.

Also, if you shoot someone who is lying prone on rocky terrain their dead body sometimes gets flung high into the air. I think it has something to do with the death animation conflicting with the paths through the rocks. When you die the body rolls around violently for quite a bit and then gets thrown into the air. {F18016}