The Knock 'Em Down Triumph still seems to be bugged... I have 3 out of 5 but I continue to get triple kills extremely fast and all 5 kills within seconds of invasion with no more progress... So you can only kill 3 at once... I do that using a behemoth and then rapidly kill them again upon respawn using the same behemoth... Completing the invasion within a couple of minutes tops... Anyone have a clue what to do..?