The account of the trial of Jesus begins immediately after his arrest. Some scholars have questioned whether the Gospel accounts are historically reliable because they differ in some details from the rules found in the Mishnah tractate Sanhedrin. However, several points should be considered.
The Mishnah was written around AD 200, while the Gospel of Mark was written in the late AD 60s, more than 130 years earlier.
The rules in Mishnah Sanhedrin describe what later rabbis believed should happen in such trials. They do not necessarily describe what actually happened.
It is uncertain whether the Sadducees who led the Sanhedrin would have followed the Pharisaic rules found in the Mishnah Sanhedrin (see Acts 23:6–10).
Some rules in the Mishnah Sanhedrin differ from what the Jewish historian Josephus wrote.
Laws were not always followed in practice. Jesus was being tried by a court that had already decided the outcome and only needed a charge to justify the sentence (Mark 14:55).
There is no strong reason to consider the Sanhedrin Mishnah more reliable than the Gospel accounts if the two differ.