One of my favorite Elo bugs I came across was a bug in a game called age of empires 2: DE.
Whenever my friend and I played online together, we would sporadically get absolutely creamed. We started looking up the stats of the others players we were matched with and noticed that on those bad games the average Elo of our opponents would jump to >2k Elo vs our barely 1k.
Both of us being software engineers, eventually the conversation turned to “What the hell do you think is going on here? How does a matchmaking bug like this crop up?”
Eventually we came to the conclusion that they must be summing out Elo for the Elo of our matchmaking party rather than averaging it.
Eventually the issue was patched and our worst suspicions were confirmed that indeed multiplayer party Elos were summed instead of averaged.
Whenever my friend and I played online together, we would sporadically get absolutely creamed. We started looking up the stats of the others players we were matched with and noticed that on those bad games the average Elo of our opponents would jump to >2k Elo vs our barely 1k.
Both of us being software engineers, eventually the conversation turned to “What the hell do you think is going on here? How does a matchmaking bug like this crop up?”
Eventually we came to the conclusion that they must be summing out Elo for the Elo of our matchmaking party rather than averaging it.
Eventually the issue was patched and our worst suspicions were confirmed that indeed multiplayer party Elos were summed instead of averaged.