I encountered the problem last day, just follow the left wall of the passage to the manor. There should be a trapped-chest but invisible at the moment (or not popped). But the quest can be completed after walking along the left wall.
Nacht wrote:I encountered the problem last day, just follow the left wall of the passage to the manor. There should be a trapped-chest but invisible at the moment (or not popped). But the quest can be completed after walking along the left wall.
Thank you! Walking over the chest did the trick for me.