Tony is eating a sandwich while talking to Chris. Every time they show the sandwich the bite continuity changes.
When Chris is on the bench next to the homeless man around 42:40 the shot is being played in reverse. There is a woman in the background pushing a pram walking backwards.
When Tony and Chris are talking in the café at the swimming pool, the sandwich in Tony's hand has its corners bitten off in one shot, but the corners return in the next.