if you see the replay, Pogba didnt get back to cover the space infront of Ndombele, which forced Fred out to press the ball, Shaw was out on left flank to confront Aurier who was high up, and Maguire was marking Moura who came inside, which means Lindelof comes out to cover Kane & AWB tucks in (Rashford was supposed to get back here to cover the space behind AWB), Maguire was late to follow Moura who ran into Kane's pass, he probably thought Lindelof would clear it but Lindelof missed the ball, so Maguire was not out of position per se, but the team was out of shape in the phase of play which allowed Spurs to take advantage and we know Kane is excellent one touch passer and he laid it nicely to Moura who crossed to Son to score.