Continuity mistake: When Aunt Clara is in the kitchen with Tabitha, when Tabitha knocks off her plate then the unicorn, there is nothing on her high chair tray. When Tabitha twitches the pot and spoon over, there's suddenly a Graham Cracker on her tray where the spoon lands.
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.
Continuity mistake: When Samantha goes back to the 15th century, Geri O'Toole is wearing a yellow dress. When Samantha pops back home, Darrin is wearing Thea Ames hit but Geri is wearing a pink dress. It all happened the same afternoon/evening. Geo should still be wearing the same yellow dress.
Continuity mistake: When Sam and Endora are talking in the foyer, the glass-paneled door at the end of the hallway is closed. When Darrin is seen in the study moments later fighting to get the chair in the closet, the door can be seen against the wall in the hallway, as it would be in the open position. When Darrin stumbles out of the study a moment later, the door is closed again.
Factual error: Benjamin Franklin is portrayed as a gentleman in this episode and the previous My Friend Ben episode. In this episode he dates Aunt Clara at the end. In reality, Benjamin Franklin was a cad, a womanizer and a playboy. He was a marvellous man - a genius - but treated women terribly refusing to marry his common law wife, abandoning her for years while he played with other women in Europe... and treated his daughter like a second class citizen.
Continuity mistake: It's understandable with Tabitha being so young, but when she is on the couch and doll is zapped next to her, the scene editing is very choppy. Tabitha scoots about 8 inches to the right (center of couch) and is turned. It's very noticeable when looking at the green couch pillow beside/behind Tabitha.
Continuity mistake: The front door in the episode is white with no window at the top. The door is normally green with a half moon, frosted, window at the top. At the end when Ho Ho comes with Pony then Larry and the client show up the porch is also flatter and different.