The Taylors in Hollywood - S6-E8
Revealing mistake: While Andy, Aunt Bee, and Opie are at the Hollywood studio watching a scene being filmed, when Andy mistakenly stands up and interrupts the filming we can see the wall and shelves behind the director, and it should look familiar because it's the wall and shelves from Floyd's shop in Mayberry.
Revealing mistake: In a recent episode (April 08), Lloyd referred to Steve as Simon during a conversation in the Rovers. Simon happens to be Steve's real name. Oops.
Revealing mistake: While Grandma Dynamite is on the roof sending smoke signals, Sonny is standing in the tree. When Sonny starts laughing we can see the bottom of his jagged clothing is now a mere straight line and his legs have vanished. (00:16:45)
Revealing mistake: In the episode "Hoofs And Goofs" (1957), just as Birdie (Moe in drag) is coming out of the kitchen, a fake Moe's face is revealed from the side as he's walking away (used to replace Moe since the real Moe was playing Birdie in the same frame).
Where Is Chick Lorimer, Where Has She Gone? - S3-E13
Revealing mistake: Tod parks his car across the street, facing left. While standing in front of the house Ellen and Peter run to Peter's vehicle and drive off to the right. Tod goes back across the street and gets back in the Corvette. The image is then flipped to give the illusion that he is driving in the direction Ellen and Peter went. (00:21:00)