Ok I'll start slow so you know I understand the nuances of the challenge. Yesterday me and a random group completed the challenge on hard mode and they all got the reward and I did not. I thought maybe it was because I died at the end of holding the aura and did not dps him. So not getting the reward for the challenge I completed it again on hard mode today and the chest appeared and right when I got to it it disappeared. So for completing the raid and challenge I got 300 boots and 303 scout rifle (not even a harrowed). I'd like to contact bungie but this is the only avenue I found. The only way to lvl up my character is through challenges and without that I might as well stop playing.