Contradiction with Matthew 26:35
Peter insists he will never be offended, while Matthew 26:22 shows disciples being sorrowful and questioning themselves.
Matthew 26:35: Peter said unto him, Though I should die with thee, yet will I not deny thee. Likewise also said all the disciples.
Contradiction with John 6:64
Jesus knew from the beginning who did not believe, while Matthew 26:22 depicts disciples uncertain.
John 6:64: But there are some of you that believe not. For Jesus knew from the beginning who they were that believed not, and who should betray him.
Contradiction with John 13:21
Jesus directly indicates the betrayal, but in Matthew 26:22, the disciples are in doubt and questioning.
John 13:21: When Jesus had thus said, he was troubled in spirit, and testified, and said, Verily, verily, I say unto you, that one of you shall betray me.