Chroma Quest LVl 72 bug

[delian]

hello i need help i found a bug  i have been trying for 4 days now to complete my lvl 72 chroma quest ive had friends help me  trying to get the item i need  but for some reason i dont get it and not all the mobs show up  i can only do this quest once a day since the required item to get into the instance disaperes and you cant retake the quest please help