Other mistake: Samantha is reading a 4-line note from Endora. The paper is semi-transparent and in a shot from the front, we can easily see the writing through the paper. However, after the note is "twitched" into a second, shorter note, there's another shot from the front - and the lettering looks exactly the same as it did before. (00:16:40)
Other mistake: When Darrin is first shrunk we see that his clothes are unaffected by Endora's spell (they don't shrink). So, when he was popped back to normal heights, his clothes shouldn't be affected, and he would burst out of them. We already know his suit changed colors.
Other mistake: While Gladys Kravitz is standing in front of her house, which is across the street from the front of the Stephens' house, Gladys sees the Stephens' backyard just as Sam zaps a swimming pool and then zaps it away, but since the Stevens' backyard is located behind the house where the living room and dining room are, this would be impossible even for nosy Gladys Kravitz.
Other mistake: The exterior scene when Clara parachutes in is not the real outside we see throughout the show with neighbors including the Kravitz across the street and fewer trees...and no pine forest. Also, it's obvious Marion Lorne, who was about 80 at the time, was sitting on a swing like apparatus being lowered... understandably.
Other mistake: When the police pull up outside the Stephens' home, it is a set shot with fake background. The "road" doesn't match the outside of Stephens' neighborhood shown throughout the series with the Kravitz house across the street (and not a pine tree forest as shown here).
Other mistake: This episode is merely a redo of the Ben Franklin episode in Season 3. The plot is the same. The dialogue in many parts is EXACTLY the same. The courtroom dialogue is the same as the courtroom episode of Ben Franklin. In both episodes, Samantha acts as the attorney even though a lay person is prohibited by law of practicing law... pretending to be an attorney.