Weird! The NPC should take the item from you when talking to them. Are you sure you have the correct one? (the void bottle 3)
I ended up restarting the game and it fixed it -- I don't know which void bottle I had, at some point I was just bringing every one I could find to the Historian, so it's very possible I mixed it up with another and just missed it!
OK, good to know! :)
