Visceris map boss unkillable

I was running an overgrown ruin and when I got to the boss I killed both his adds before he went to his 2nd health gate, after that he became unkillable.

I was not using southbound gloves or any other item that would prevent me from killing something and was also not using the Ancestral Bond keystone.

Link to the character:
https://www.pathofexile.com/account/view-profile/Matchstick1/characters/lucinc

A short video to show what was happening:
https://youtu.be/pMU3cKTCTWE

I believe that's related to this bug: https://www.pathofexile.com/forum/view-thread/2184002. If that's correct, it seems that AoE skills are required to trigger the bug.