3. bug? / problem with the bookcase in the basement of an abandoned village:
team persuasion detects scratches on the floor next to the shelf with a passage behind it. One could not move this rack in any way or destroy it. \
(Attempting to insert the Necrotic Immunity recipe book and Dark Amethyst doesn't help either)

So there is a hidden lever to open this shelf. It's not easy to find but it is there and works. Don't really want to spoil it since I'm sure there are other sites that already do this.