Sounds like a lot of people are destroying one from the Nexus set, then going into the Well of Infinitude and destroying two from that location's set of three. - Drones are available in multiple locations, it isn't one visible location per week (it is the consumable that lets you scan them that is limited). I've seen them in Braytech, Creation, Nexus and the Well of Infinititude this week. - All three sets of drones will be visible in a location, you don't need to destroy them in order, or destroy one set to make others appear. - The buff will tick down once per set of drones destroyed and give a reward when you do three. They don't 'have' to be all three in one set, but there are triumphs for completing a set. So it's neither a bug nor an issue, for people to be destroying drones from different sets. They'll just have to remember next time they get the consumable that there's one more in the well and two more in the Nexus, to complete their respective triumphs.