Noticed the floor near Black Maw boss (near a troll and skeleton mob, right above a door to the temple) isn't even with the surrounding area. Literally drops down like a ledge. Standing from Black Maw's side you can't notice it. With the 'ledge' there it makes it difficult to fight the mob located there. There's another spot I came across but it wasn't as noticable and I don't remember where it was exactly.