NPCs didnt spawn after act 4 boss

I beat the act 4 boss, and sin's animations with the weapon play, but none of the npcs required to continue are present and interactible. Their icons are on the minimap, but they are not actually present. I have to redo the whole zone and boss fight.

For quests, I only have the 'witness the hooded one" and "fate of the vaal" active.