Even in the earliest versions of the NT we see two synoptic evangelists responding to the earlier text of Mark, and deliberately changing it, because the earlier text does not accord with their idea of Jesus. A typical example of this is Mark stating that "Jesus was angry"*. Matthew and Luke obviously didn't like the implication of this**.
*Mark 1:41
**Nor did many translators. The NIV is honest enough to translate this "Jesus was indignant", though early texts prefer to skew the Greek to mean "Jesus was moved by pity". Since Jesus has just been asked by a leper to be cured, it's easy to see why from the earliest times the text has caused translators and commentators a degree of confusion. After all, Jesus has just informed the assembled crowds, via a text from Isaiah, that he has come to "heal the sick" and all kinds of other wonderful things.
Perhaps you can provide the Greek phrase that you believe means 'Jesus was angry' in Mark 1, Dicky.
In most texts, that phrase would be splagxnízomai/σπλαγχνισθεὶς (compassion/pity) but we also have the Codex Bezae in which it is written that Jesus, instead of showing compassion displayed anger: orgízō/ὀργισθείς which correlates with the end of the passage where Jesus
orders the guy not to tell anyone.
There is good reason to accept the original phrasing was orgízō over splagxnízomai as the scribes of the later stories chose not to include either phrases in their writings; Matt 8:3 and Luke 5:13 respectively. If the original they were copying from had used compassion instead of anger they would have had no difficulty in saying so, but an angry Jesus at a reasonable request from a sick man was not the sort of Man they wanted to portray.
Which also explains why the later copyists of Mark chose to replace angry with pity!!