My fireteam did the Sword Dance cyst several times without dropping the first sword you get from the entrance and also without dying the whole time and the triumph is not popping up. I've done solo runs without dying or dropping the sword and it's not working either. If you check stats websites, you can see nobody has the triumph yet, so I can certainly say the triumph is not working properly. Maybe when you finish the lucent hive bosses the sword "disappears" in the middle of the animation and it counts as dropped or maybe when you kill all lucent hive bosses you lose the sword too and it counts as dropped. But technically, you don't drop the sword, because it doesn't float on the ground. Please bungie, acknowledge this bug. Thanks.