Online Draft vs 3 Players? Hacker or Co-Op?

How is it possible to play Online Draft against 3 players? I just had a match where it looked like I was playing against 3 different people on one team. Is this a hack, or is there some way to play co-op in Draft that I don't know about?

https://www.youtube.com/watch?v=f1g0OluAGuY&ab_channel=Calvin