So I found my own answer. I played the Reno fight on Easy mode. Got the Turk to half HP when the crossed circle popped up over his health bar. I kept swinging away. Even staggered the b-. But his health didn't move. This didn't happen when I fought Abzu. I was able to drop that shoat before he could even use Backwater Blast. This is a shait game mechanic IMO.