Other mistake: When David takes a book from the bookshelf and opens it, a small piece of paper falls to the floor. Neither he, Ozzie nor Harriet notices it.
Other mistake: Ozzie has just brought the mail in. He says, "Here's a bill. Here's another bill." Instead of looking at the rest of the mail, he hands it to Harriet, telling her, "I've had enough bills for one morning." The time on the clock is 4:15.
Rover Boys - S1-E18
Other mistake: David's teacher is called Mrs. Fraser in some scenes and Miss Fraser in other scenes.
Other mistake: Cathy Calhoun is knitting a pair of socks for her brother, and offers to make a pair for Ozzie. She tells him, "If you really like them, I could get some more of the material." Knitting is done with yarn, not material. (00:06:50)
Other mistake: The clock shows the time as 2:20. Ozzie goes outside and spends five minutes talking with Mr. Thornberry. When Ozzie comes back inside, the time on the clock is still 2:20.
Other mistake: Harriet phones a plasterer to repair a wall in the boys' bedroom. He says he will be there the next day. Ozzie phones Mr. Baxter and asks him to replace a broken rain gutter. Baxter comes to the house and tells Ozzie he has two big jobs to finish and "it will be about a week" - but he shows up the next day, same as the plasterer.
Other mistake: Ozzie says the fiscal year of the Men's Club runs from September 15th to September 15th. A fiscal year beginning September 15th would run through September 14th.
David and the Stewardess - S6-E15
Other mistake: Rick is playing an acoustic guitar in his bedroom, but the sound we hear is that of an electric guitar.
Other mistake: While Rick plays guitar and sings at a dance, the drummer behind him appears to be playing but never touches the drums or the cymbal with his drumsticks.
Other mistake: Five young boys in Ozzie's backyard are pretending to shoot each other with toy guns. Ozzie pretends he's been shot and falls to the ground. When he sits up, the boys compliment him on the way he "died great." Ozzie then tells them about his great-grandfather, a gunfighter known as Six-Gun Nelson. Following a fantasy sequence with Ozzie portraying Six-Gun Nelson, Ozzie is now magically wearing a gun belt with two holsters and two guns.
Other mistake: As Clara and Harriet are driving home from an antique store, the car runs out of gas. In the close-ups, the car has no windshield.
Dave and the Teenager - S11-E17
Other mistake: When the Harris family moves into an apartment across the hall from David and June Nelson, their 14-year-old daughter, Betty, develops a crush on David. When David and June step out onto their outdoor patio, they see Betty watching them from her own patio. This could not be possible.