Bugs in Quests - General! (The Witcher 3: Wild Hunt)

I did not find a topic on the forum on the problem in my quest, I decided to create a general one for discussing problems in quests. One place is more convenient.

I have a problem specifically in this quest
Spoiler I bought everything from him, the pointer hovered on it, the items in his inventory are updated every time, even those three that are marked as for the task. I found the destroyed house of Azramas, collected everything there, pulled some kind of lever, darkness for a couple of seconds and nothing. Nothing happens to the icon, it says that I don't have the right key. What, what key, where!? Bug?