Chaos zone 9 difficulty

Hi guys so I am currently on chaos zone 9 difficulty on new event. I am easily able to go till area 2 last boss. The elites and normal enemies before last boss are cake walk but the boss is insanely hard with like 38k HP. Is the balance correct? Or it could be because any before selected actions? If i am able to easily beat areas just before it wouldn't boss be the same (that was always the case for past 8 difficulty zone in this chaos zone)

Also anyone else experiencing +1 AP generation skills not generating AP on use? This happened to me way too many times and its kinda random. Sometimes it generates but most of the time it doesn't.