I got a weird bug with my newest character in Bluerock castle. When checked the shelf to get one of the necromancy tomes, I got some generic chest opening instead. Revisiting the map later didn't help.
I'm sure I didn't get the tome before, since I hadn't visited that part of Bluerock castle before with this character since the map was still blacked out.
You can export your data and email it to me at [email protected]
so I can check what happened. At any rate, did you sleep 12h before trying the area again?