You need to understand the absolute bliss of finnally beating that fucking ape, after hours of trying only for you to decapitate him, then the arm reaches over and picks up the head for the second health bar. Do you know what the reward is after days of attempts? 20 minutes later, you fight two at once, and you’ll do it like it was stomping a goomba in Mario Brothers.
These things are equally likely until we have more information.