LAW 18.3 - Short runs
(a) A run is short if a batsman fails to make good his ground in turning for a further run.
(b) Although a short run shortens the succeeding one, the latter if completed shall not be regarded as short. A striker setting off for his first run from in front of his popping crease may do so also without penalty.
They ran back for two, so it should've counted for one. Terrible umpiring.