Problem with the quest "Vaal Legacy"

When completing the quest, I mistakenly went to a normal level and seeing that the soul core was already inserted, I somehow threw the soul core out of the inventory. When trying to insert the core in brutal mode, the animation of inserting the core occurs, but after that it does not appear and the water does not go away. When trying to re-pass the "Sanctuary" location and kill the boss, the new core does not appear.