Other mistake: The opening credits for season 5 show June coming out of the front door with a pitcher of what looks like iced tea, and calling for Ward, Wally and Beaver who are all working outside. But the door opens by itself as she comes out, and then closes by itself behind her. If the entire family is outside, who opened and closed the door?
Continuity mistake: As Beaver and Wally are starting upstairs after Ward asks them to go change their shirts for supper, the camera cuts from a long shot of Ward across the room in a chair reading a newspaper, wearing a light grey suit, to a medium close-up of Ward wearing a much darker suit, and then back to the light grey.
Continuity mistake: As the family is sitting at the breakfast table during one of the very first scenes, Beaver gets up to leave for school. The checkered napkin in his lap falls to the floor as he walks to the back door. The camera cuts back to the table where the napkin has magically reappeared.
Continuity mistake: After Eddie and Lumpy show up to help The Beav and Wally load the lawn trash into Lumpy's car, Eddie places a lampshade and a woman's hat over a burlap bag of trash and jokes it's Lumpy's date: "Who says Lumpy can't get a girl?" Just then the camera cuts over to Lumpy who says "ha ha ha." The street is at Lumpy's back and a car is driving in the background towards Eddie. When the camera switches back to Eddie, Lumpy approaches Eddie. The car should drive past, but it never does. (00:14:37 - 00:15:40)
Continuity mistake: When June is talking to Wally, she's wearing a wristwatch and her wedding ring on her left hand. But in a close-up shot of her hands while she's making a sandwich, her left hand is bare with no watch or ring. Back to the wide shot, and the watch and ring are on her hand again. (00:05:25)
Visible crew/equipment: June and Ward are in the kitchen, Eddie leaves and Ward and June continue talking about Eddie and Wally getting hired at the dairy. The next scene shows the exterior of the house, and a dark figure is seen walking from the house toward the garage on the left side of the screen.