known and posted before.
I assume this has to do with the way the game has been coded;
when a 0|1 creature is overdrived, it will still deal 3 damage before dying.
Thus, we can conclude that damage is dealt before overdrive deals damage,
however, it happens in the same frame.
For some reason, it cannot show 2 different new damage-numbers in the same frame,
resulting in the latest damage dealt that frame to be shown.
Which is the damage the doll takes, applied to the opponent.