Call of Steel / Searing Exarch HP bug

There is a bug with the searing exarch where my Call of Steel removes all impale stacks on the Searing Exarch Boss, but no damage is dealt. This is the third time it has happened, at first I thought it could've been a fluke, but it is consistent to reproduce.

This is the video of the encounter: https://youtu.be/aGXybAnTna4

It is worth noting that when my crushing fist deals less damage than shown in the video, Call of Steel works as intended and does remove impales AND deal damage to the boss. In my situation as seen on the video, I specifically hit the boss with enough damage such that Call of Steel will kill the boss after removing all impales (it has sufficient damage to do so) - no damage was dealt.

But when call of steel does not have enough damage to kill, it deals damage as intended.

Funnily enough, consuming the impales with attacks (without call of steel) will work. Which implies this bug is _specific_ to call of steel - something in the calculations is flooring the damage value to 0.