So I know everyones all hyped after Bungie told us that they've hidden a lot of surprises like The Black Spindle in various other missions now and so I just finished today's Daily "Cayde's Stash" and at the end after you beat the boss one of the last things he says to you is "If you find any more of my hidden treasure, be sure to leave it for me. there will be plenty more to find on the Dreadnaught" So i'm pretty sure thats definitely a little hint that there IS some kind of hidden exotic encounter related to Cayde's Stash mission. I know there is a video out there where people have seen the hidden room while taking the grav-lift up to the boss room. So anyways. Just wanted to put that out there, let me know what you guys think.