Played an ARAM game with a Yorik. Game lasted 25:40. He was tied with two other people for Kill Participation. Yet, in the post game screen he was listed as having done over 500k damage to champions. Our Riven did some big numbers too but everyone else from both teams was under 45k.
I just don't see how it's possible for one player to put out more than 10x the damage to champs as everyone else. As further proof, his TOTAL damage dealt was only 20k more than his damage to champs. I don't see how a guy does 10x more damage than everyone else, but has the 4th lowest # of kills, no more total kill participation than anyone else, and manages to only do 5% of his damage to 'not champs'.
It has to be a bug.