No Soul Core in Jiquani's Machinarium

Was playing with a friend, first 'stage' we found some bugged out walls and no soul core at any reachable place, had to create a new instance (which worked then).

Same just happened to me. I walked into Jiquani's Machinarium immediately post the chimera fight, killed all available mobs but no small core dropped.

After resetting the instance it was on a dead mob that I didn't kill. locked behind a closed door but was already dead.