Sorry, jumping in on a late thread but I'm running into similar issues and you seem to have some idea of how the exotic RNG is supposed to work. 1. I have the "Crest of Alpha Lupi" for my Titan. I very much want the Armamentarium and the Twilight Garrison. Oddly, in the exotic armor kiosk, it only shows 2 titan chests available for year 2, not 3. Are both still available? 2. Since getting the "Crest", I've gotten 5 more exotic chest engrams to drop via 3 of Coins. Opening them with my Titan, they've opened as 2 ATS/8 Tarantella, 1 Heart of Praxic Fire, 1 Alpha Lupi for the Hunter, and yet another Alpha Lupi for the Titan. So 4 out of 5 weren't even for a Titan and the one that was was a duplicate. According to your numbers there is a 67% of a piece I don't have dropping, but that seems high based on what I'm seeing. I've had even worse luck with gauntlet engrams and trying to get the "No Back Up Plans", but I don't have solid numbers for that, just a stack of useless gauntlet exotics waiting to be sharded. Seems that the exotic RNG is a bit broken at the moment, especially for the effort and cost in involved in getting the engrams in the first place.

I wanted to reply to your post right away, but I didn't want to have to type it all out on my phone. I've had enough time to play with RNG with other games and I really only understand the concept. I don't have any exact math to back up my views and a lot of my information is based on the community's beliefs. Please allow me to answer your questions as best I can. 1. I can't really explain why it would only show 2 exotic chests available for Titan. I have all three listed on mine, so I suspect it is just a visual glitch in the kiosk. To my knowledge, no exotics have been pulled from the kiosk, but players have reported certain exotics not appearing on the Kiosk List (like Peregrine Greaves. Apparently, the kiosk slot for it is actually MK44 Stands Aside. I've never owned either, so I can't confirm that.) 2. This one is going to require slightly more work to explain. Yes, based on my numbers, there should be a 67% chance of getting an exotic chest you don't have, but my original numbers didn't take into account that Bungie has exotics set up to check every exotic chest available in the game regardless of class. That skews the numbers quite a bit since players don't actually know if the class for the exotic is determined before the item itself. This unfortunately means there are two ways of thinking about this. The first is that Class is determined first. Players have long suspected that the class that decrypts the exotic has a higher chance of getting something they can used. I can't say if this is certain or not, but I also can't disprove it either. If it is something that is considered, it means the class that opens it has something like a 40% chance to get something they can use vs the normal RNG value of 33%. Taking that a step further, if that class is chosen, the game looks at the exotics you have and don't have and alters the numbers accordingly. In my original example, the game should (theoretically) have a 67% chance of giving you a titan exotic chest you don't already have. That means the actual chance you have to get one new exotic chest is actually closer to 26.8% whenever you decrypt an engram (.4 [Class Picked] x .67 [Chest you don't have]). Granted this is higher than 1/4, but still low enough where you are likely to get a string of misses like you encountered. Unfortunately, that's the total chance to get one of two chests you don't already have, so it doesn't feel much better than a damn coin flip, dropping the odds to get a specific one you don't have, like Twilight Garrison, down to 13.4% from the second you decrypt that engram. The more I look at Destiny's RNG, the more I suspect that the game doesn't really work that way and the more I think the game just looks at the absolute total of exotics in the game. In the case of Exotic Chest pieces, there are 11 Year 2 Chest Pieces available right now. 3 of these belong to Titan, 3 belong to Hunter, and 5 belong to Warlock. Right out of the gate, you're already disadvantaged if you're not a warlock. The chances of getting say Twilight Garrison when never had an exotic chest on any character is 9.09%. Even if we assume that Bungie is right and that the game is weighted to favor giving you an exotic you already own, the margin (in the grand scheme of things) is really minor and the chance of getting an item like Twilight Garrison is probably not much better than 11% to 12% for any chest engram you decrypt. What I am getting at is that my original math didn't go far enough and made it seem like your chances were slightly more favorable than they are. For that, I am sorry. It was never my intent to mislead anyone. I simply didn't explain this in the right way nor did I actually take things the extra step to put things in perspective. I still stand by my view of not decrypting more than 2 at a time without logging out and back into the game.