Continuity mistake: When Monk is leaving Derek Philby's classroom, he is quite content to just pick up a piece of chalk (with his bare hands) to write on the blackboard, but earlier, he makes sure to use a chalk holder to do this and nearly has a panic attack when he gets chalk dust on himself.
Character mistake: Sharona invites Monk home for dinner. Monk is playing with his food, and Sharona guesses it is because the potatoes are mixed together with the carrots. Sharona asks Kyle to fetch two plates (So Monk can separate the potatoes and carrots.) As he tilts the dinner plate, Monk succeeds in scraping all the carrots onto one dish - save for one stray potato - all the while speaking. He completes his thought without removing the stray potato. In all other instances, Monk cannot allow such a transgression. He either corrects it before saying his piece, or after. But he cannot let it go.
Character mistake: When Kathy is presenting her model of General Robert E. Lee's surrender to General Ulysses S. Grant on April 9th, 1865, she incorrectly states that the surrender occurred "at the courthouse in Appomattox, Virginia." The surrender didn't take place at the actual courthouse, but rather at the McLean House, a private residence selected by Grant and his aides for the meeting of two of the greatest generals in American history. This is a common misconception as the village itself is called Appomattox Courthouse. (00:29:05)