It got retaken because the penalty was saved, and the person who scored the rebound encroached. The thing is, Wan-Bissaka also encroached, so it cancels everything out, basically meaning that the pen should be retaken.Don't see why a pen should be retaken if the defender encroaches but the attacking team still score......
Retaking the pen only serves to potentially disadvantage the attacking team by creating a second opportunity to miss.

