Essence boss damage?

While grinding essence, I tend to stick around a comfortable level to maximize the diamonds spent per 4 chances and reducing the chance of a death - essence is incredibly valuable! I’ve noticed something strange, though. After grinding the same “safe” level repeatedly and for some time, (I like to stick to 16) I notice that after around 16 repeats on the essence boss (be it for hunter, sorcerer or warrior) it will gradually hit harder and harder, frequently one shotting my team even with the normal active mitigation from skills and the gear I have. There have been instances where I enter the same floor (16) I was having no issues with a moment earlier only to get swiped for all of my available health immediately. It isn’t one of the big attacks that are broadcasted with a timer that can be easily interrupted - it’s almost like I’m being rapidly auto attacked harder and faster by the boss the more attempts I grind.

Essentially, it feels like the difficulty for the essence boss is somehow ramping up despite staying on the same floor. I’m being cautious about spending too long farming essence now because I don’t want gems to go to waste, but is this just a case of bad luck with numbers on my end or is there some sort of a bug here? I’ll see if I can record this happening just to show that I’m not crazy lol.

Thanks!
Update: I was able to successfully recreate and record this phenomena happening while farming floor 16 for blue and red essence if there’s any way I can send it to someone on the dev team. You can watch the damage begin to ramp up higher and higher as the run goes on - at one point with damage mitigating skills active, I take insane damage.