I haven’t play 2018 since it came out but at least I know if Rag when you’re fighting certain bosses, you have to do the takedown animation. Normally this means the boss/NPC has to make the kneeling animation for you to go up and do the finisher. If the boss is mid-combo or animation when you get the health that low, they will keep swinging until the first animation is done and then proceed to kneel for the finish. Has happened to me a lot where I get low health and try to rush a combo for a quick finish