So I could be wrong, but I was under the impression that if anyone received a gold tier in a public event, they were to receive an Ascendant Shard (along with Ascendant Energy). Out of the last 5 events that I have scored a gold tier, I have only gotten one Shard and the other 4 times I didn't get anything at all aside from rep. I still get the rewards for the first event of the day, though. As I said, I may be mistaken and the rewards could just be random, but I feel like I've been cheated out of 4 Shards at this point. It's really frustrating because it's one of the few ways to to get materials to upgrade my legendary armor, but I'm not making any progress.