Because of the small humps and bumps in the cave areas in Camelot Castle, its difficult to attack and do dmg there. Even if you see the whole target, I cant nuke or hit with specials etc, because it is "No line of sight".
Same is everywhere really, as long as it is a small hump/bump between you and target, you cant hit.
Must be adressed, the small humps cant ruin fights like that.