Has Harmonious Arrow always hit the 50 damage twice or is some sort of dot extension screwing with it? Had an issue where the pull failed, I faded off the 4 mobs then 6 seconds later it hit initial mob again and they all reaggroed.
Went through about 3 years of logs and it seems it has always done 2 hits. Never had an issue before so it must have just been bad timing of the fade.