I was doing the '15 Men on a Dead Man's Chest' quest and encountered some difficulty. So, I dug a bunch of holes all around the chest, and then opened it to trigger the drowned appearing. My tactic was almost foolproof (3 of the 4 fell in the holes), but I noticed something about the ones that fell in the holes. When I ran outta "bullets", I jumped in a hole with one to finish him off with saber. However, the drowned just stood there inert and let me whack away. It was like the AI just turned off because he was a in a hole. Seems like a bug, but one I'll be taking advantage of until it's fixed. Huzzah!
#[BUG] AI Disabled by dropping enemy into a hole
full skiff