Continuity mistake: When Samantha opens the door, you can see the 3 pictures by the door. The middle picture is straight. When the camera cuts to Samantha and Aunt Clara and returns to Larry at the door, the middle picture is crooked... a necessary plot point to distract Larry from the desk in the stair case.
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.
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: 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.
Continuity mistake: When the coven is reading the case against Clara, the gable is lying in the middle of Judge Bean's Bench. The camera cuts to Darrin then returns to the Coven, who is still reading their case against Clara. The gable is suddenly on the wooden platform. There is no indication the gable had been used as the coven is still reading their case against Clara.
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.