Wolves overextended their two-goal lead to lose 3-2 to second-tier Ipswich Town, and Luton Town lost 1-<> to third-tier rivals Exeter City.
Exeter held on after Dimitri Mitchell was sent off for a second warning five minutes after scoring the winner in the 83rd minute.
Burnley, who are still winless in the Premier League this season, beat fourth-tier Salford City 4-<>.
Goalkeeper Dean Henderson, who moved to Palace from United earlier this season, was injured in his debut for his new club to come off in the 19th minute.
Goalkeeper Sam Johnston, who started his career at United's academy, conceded two minutes after he came on with a shot from Alejandro Garnacho.
Brazilian Casemiro made it 2-27 with a header in the far corner after a corner kick from Mason Mount in the <>th minute.
Anthony Martial added the third goal to score his first goal of the season after a pass from Casemiro ten minutes after the break.
Palace visit United again in the league on Saturday.