Nottingham Forest manager Sean Dyche described the decision to award Manchester United a corner in the build-up to the visitors' opener at the City Ground on Saturday as "farcical".
Nicolo Savona's clearance from Bryan Mbeumo's delivery was heading out of play, but the Italian full-back chased after his own header and appeared to stop the whole ball from crossing the byeline.
However, linesman Akil Howson signalled that the ball had gone out of play, prompting referee Darren England to award the corner - from which Casemiro put Ruben Amorim's side in front in a game which ended 2-2.