I purchased the three of coins thing from xur then i went to a random boss and used it but i died at the same time that i killed him. When i died i noticed that he dropped a yellow engram (exotic) not green but yellow, then when i spawned back up it wasn't there nor was it in my mail. So i don't know if this has happened to anyone else but i feel like its a pretty big deal to loose an exotic engram after you paid for the for the chance of getting one. I guess its just one of those things that will happen and i shouldent make a big fuss out of it but still i kind of feel a bit upset and dissapointed that i lost something so valuable (in game).