Revealing mistake: When John Boy goes out of the kitchen angrily, the view of the back is different than what it actually is. From the kitchen, there appears to be the mountain and trees, but when John Boy is outside leaving the kitchen, we know the barn is what we should see from the back door/window.
Revealing mistake: When Maryellen runs into John-Boy's arms (after running away) Richard Thomas (John-Boy) breaks character as he looks into Judy's (Maryellen) eyes, by swallowing hard. Like a guy would do, when he's close to an attractive girl. Then later covers his groin with the cast, when John and the kids check up on him. The two young actors playing Jon-boy and Maryellen crushed on each other behind the scenes.
The Carnival - S1-E3
Revealing mistake: When Jonboy, Jason, Ben, and Elizabeth are trying to lure the monkey down from the tree, the leash it's tethered to is visible down the tree trunk. But then disappears after the monkey climbs down.
