POE 2 Forgemaster boss break bug 2 phase

Hello
I was recently doing the Forgemaster boss and found out that if you stun him (reach the max for the yellow bar under health) while he is going to do the lava phase (start walking and summon lava) it will get bugged and only walk towards you and dont attack you.
Bug Report ID: #4020565342

I dont know if I can provide with more information, hope this description helps