Well damn, apparently this bug is back after the recent Hotfix. You should tag this for the Support section, and I will reiterate. When the first "Fusion Rifle Nerf" patch happened, the Vex Mythoclast (only in PvP) would sometimes glitch if you died while shooting it at the same time, causing it to act like a normal Fusion rifle, and firing a round of 7 torrents (3 shots total for a 21 round clip). It appears that the Queenbreaker's Bow now also suffers from this infrequent bug, and since it only has 6 rounds in a clip, it shoots all 6 torrents.