This just happened to me too. I thought the only thing I had to worry about was already having a cipher, because like, yeah, the game is absolutely clear you can only have one in your inventory. HOWEVER, it turns out that having zero ciphers doesn't actually matter when your inventory is full, because it'll just evaporate your "new" one too. I spent all evening playing GMs, gambit, and crucible with friends, and I had an awesome time! To cap things off, I went to turn in Xenology and realized I received literally nothing. That really bummed me out! Like, dang, thought I was gonna finish the night buying a cool new exotic or something. I'm disappointed over this being somehow the "official" case for the item, too, not to mention it being one of the most rare items in the game. The highlight text for Ciphers says you can only have one in your inventory, which I'm fine with, but the game opting to make it vanish into thin air [i]even though I didn't have one[/i] feels horrible. Can't even move it to my postmaster or have Xur hold onto it? No warning or anything? Nothing in the UI to tell me this would happen? I had to find out [i]after I googled this issue[/i] just to see a bunch of people who've had this happen for [i]years?![/i] it's especially [i]really[/i] nice reading years of the community's comments on this, too! Nothing like feeling freshly scammed out of an item that I get maybe one or two of every month, and then finding out this has been a [i]known "issue"[/i] for years, with dozens of posts from people who've been dealt the same unlucky hand, then seeing a bunch of people say "that's how it's always been, guess you should've been paying attention" because apparently a bunch of people in the community blame the people this happens to?! People from this community, [b]including community Mentors,[/b] basically saying this weird tautological "well it's just how this has been forever, you should know this because you should have known this" Somehow, it's [i]our[/i] fault for not paying attention to our inventories, because there's no indicative reason to believe this would happen? It's [i]my[/i] fault because I assumed it worked like literally every other item in the game? Absurd.