I can't fight the 3rd boss of the interlude

I was playing like usual until I died once and I saw a soul core drop again, weird but nothing bad. Then I was fighting the boss, I killed one of them and the other was like at 10% health, then my game froze and I died and now I can't fight them again, they just stand there saying random words infront of the dead chubby guy and the red cristal. What do I do? I tried closing the game, dying and just standing there, but nothing activates the battle.