I can second this as correct. I went with a group who had all 6 of us with orbs for ks30s and the time we got the record, it was the person who popped the chest at the end and not the orb holder or party leader. We fought the fight, and all of us left except the person popping the chest so we all didn't have to make the trek back around through Palborough.
You'll also notice that instead of saying "(Blah blah...) the record is held by six adventurers including (insert your name here)," it just says the record is held by that one person who popped the chest.
