POTENTIAL SPOILER ALERT!
I received a strange message in the inner sanctum part of the Druid's Grove, specifically the chamber where the dissected Drow is kept. When approaching the workbench, the Dream Visitor gave me a message: "There's something in that vessel. Take a closer look". However, I've used "examine" on everything that I think could be charitably called a "vessel" in proximity to where I received the hint, and don't find anything special or revealing in the items. Has anyone else any ideas on what this suggestion is about?