I did a run of Vault of Glass with my clanmates and we did the extra oracle puzzles in order to get the Vex Mythoclast catalyst, but when I arrived at the portal to pick up the catalyst, it closed right as I approached and I did not get the catalyst. Other members of my fireteam received the catalyst. I had Vex Mythoclast equipped at the time, and have owned the gun for a while. Thanks for any help y'all may be able to provide.