Overwatch – Can More Than One Golden Loot Box Be Claimed?

The Overwatch blog has a post about the Summer Games.

Regarding loot boxes, it says:

Starting today (and for the duration of the event), any new Loot Boxes you earn or purchase will be sporting an updated look, but the packaging isn’t the only thing that’s changed!

Inside, players will have a chance to find a variety of new cosmetic items commemorating the Summer Games—including themed sprays, emotes, victory poses, highlight intros, player icons, and some very special skins. Though they can't be purchased with credits, each seasonal Loot Box you receive is guaranteed to contain at least one item from our Summer Games 2016 collection.

While any Summer Games item you unlock will be yours forever, the collection will be heading back into the vault on August 22 when the event concludes. So, if you’ve got your eye on something specific, there's no time to lose!

I interpret this to mean that all loot boxes obtained during the event will be "Summer Games Loot Boxes", and that each loot box will have a mixture of normal and summer games equipment.

I believe this is due to someone leaving and another person joining and ending the game with fewer deaths than the other person had when they left. From what I can tell, it seems to calculate the kill participation percentage by # of eliminations you get / total # of deaths other team has. So if you have 100% kill participation, and the person on the other team who has the most deaths leaves, and someone else joins and ends the games with less deaths and you keep your kill participation close to 100% after that, your kill participation would be over 100%. This would also occur if someone left and no one replaced them. I have noticed a jump in kill participation when this happens, and a number of other people report this happening to them.