Was thinking the very same thing....Ive never heard of PGMOL or any refereeing institution either being consulted or offering a judgement in the middle of the game.
For me Sterling CANT be offside....the defender has touched the ball last and you cannot be offside from when the last touch comes off the opposition...thoug they are saying the ruling says that if a player is making an attempt to play the ball even if the opposition player plays the ball onto you and you have started in an offside position then you are still offside.