Factual error: Since Monk has OCD it would be highly unlikely for him to be on a jury. Plus, Monk works for the police department and since he technically works in the criminal justice system, that would have made him exempt from jury duty.
Continuity mistake: When the man with the letter from the Attorney General is telling Stottlemeyer not to 'screw it up', he is moving the letter in his hand. However, every time we see Stottlemeyer front on, there is a corner of the letter in the shot, and the letter remains stationary even while the other agent is moving it.
Continuity mistake: In the jury room, the two windows behind Monk have venetian blinds, which are raised halfway on the right window. But in several shots of the science teacher coming over to identify the white powder, the right window's blinds are pulled down. (00:35:00)
Factual error: When Natalie hears the jury's muffled screams inside the locked room she uses the fire extinguisher to tear off the door knob. But a locked door without a knob is actually only harder to open, because like that you cannot turn the mechanism even if it was unlocked.