I’m aware of how the quest is supposed to work having the heart of flame spawn as its own entity instead of loot from ragnaros himself. Our kill of ragnaros was completed on heroic difficulty and as per the guide linked in your response i see nothing as to how anything was done wrong.
“THE BELOW ONLY APPLIES TO NORMAL DIFFICULTY. On Heroic, the encounter is unaffected, and the Heart of Flame Heart of Flame is simply looted from Ragnaros afterwards.”
please help