Contradiction with Matthew 4:1
Jesus was led up by the Spirit into the wilderness, instead of leading His disciples somewhere as in Mark 6:45.
Matthew 4:1: Then was Jesus led up of the Spirit into the wilderness to be tempted of the devil.
Contradiction with John 7:10
Jesus went in secret to the feast, contrary to sending others ahead publicly as in Mark 6:45.
John 7:10: But when his brethren were gone up, then went he also up unto the feast, not openly, but as it were in secret.