Assume a 3v3 scenario where the fight is very close. At a certain point the fight became a 3v1 because the better team eliminated two players from the other team. Now everyone is on 10% because again the fight is close and it's approaching its end.
Now, if the player that is left on his own manages to eliminate one of the 3 players that are against him, he heals to full hp and wins the fight because he has 100% hp against two players that have 10% hp each.
So to sum up:
One team played better but this mechanic made the team that played worse win.
Now, like with every mechanic - you can either cry about it or make use of it.
So if I wanted to make use of this mechanic, it would mean that if I get into a fight that is close, I need to wait for my teammates to die and only then start to fight because then we would have a better chance of winning.
Therefore, logically, making use of this mechanic contrasts with the most prevalent study of game theory because in order to have a better chance of success, you need to first put yourself in a statistically inferior position.
Case closed, this mechanic should be removed