Killed Arakaali but unable to progress.

Used Vaal Flameblast to kill Arakaali in her second phase, second and third hits from Vaal Flameblast hit, died almost immediately to burn damage, gave death animation, Yeena and Sin showed up to congratulate me on kill, but the doorway to next act didnt trigger.

I am able to see WP for act 8 but am unable to access it because "You do not have the required quest state."

gonna re-attempt the fight and kill her slower in second phase. Think I just killed her too fast first attempt.

Got exactly the same issue just now: Yeena and Sin show up, Sin says his creepy line "Death is the true climax of perverted lust" and then it just blocks all further progress.

Had to redo the zone and rekill the boss too :)