Yeah, based on what they have been trying to get used to (which seems to be less grinding for weapons and more going through rigorous steps I get) I think that this wouldn't happen. I believe that the way that the Twilight garrison was a glitch or incredible luck under incredible odds

It may be a glitch, but in the case that it's not, I think my theory is the best bet in terms of what direction we should be going to find these exotics. If it wasn't a glitch, it's more than likely an exclusive drop from a particular boss.