Well I'm stuck

Act 3
Quest
Legacy of the Vall
Return to the Encampment and find Alva at the base of the Ziggurat

Power 2 generators, take the soul core and kill the boss

I did it

and I didn't talk to the NPC about the start of the quest when she talks about generators

and she broke

she stands in the location with the generators
when doing everything again talking to her she teleports but does not appear in the camp
I can't move forward

I tried to complete the mission 3 times
but the boss doesn't drop the quest item