Revealing mistake: When Carrie (played by twins) falls down in the opening sequence, it appears that she gets back up and continues running. In reality, after falling, the other twin gets up and continues. If you look closely enough, you can see that when getting up, Carrie is slightly closer towards the camera than when the first twin fell.
Revealing mistake: In the episode where Baby Rose is sick with smallpox, you can see part of a modern disposable diaper under her cloth diaper when Doc Baker is checking for blisters.
Revealing mistake: The guys get the pregnant girl and her kids 50 lbs pounds of flour. She goes outside, people are talking about her and she runs. You can see tire tracks in the dirt road.
Journey In The Spring (1) - S3-E6
Revealing mistake: When Charles notices that his dad set the house on fire, and he is at his mom's wooden grave site, the wooden grave marker moves when he gets up to save his Pa from the burning house.
Revealing mistake: When Anna (little girl who stutters) is crying after being teased, the "tears" on her cheek are obviously fake. They never run or move. I'm guessing rubber cement.
Revealing mistake: During the scenes when they are chasing the balloon in the prairie, the tire tracks from the camera car are easily visible.
Revealing mistake: When Charles steals a horse to chase down the balloon with Carrie in it, you can see it's a stunt double. Charles is wearing his hat, beige shirt, and his knee-high boots with pants tucked in. The stuntman has a pink shirt, no hat, and long pants with shoes. Maybe even white socks.
As Long As We're Together (2) - S5-E2
Revealing mistake: When Charles Ingalls plays his fiddle at the end of the episode, one can see from the movement of his hands that he is not really playing, but just pretending. (Also visible in every other episode where Charles plays the fiddle, but most obvious in this one.).
Revealing mistake: When Laura picks up Baby Rose from Thomas Stark, the blanket is flipped up and you can see a plastic doll's leg, then when she goes into the bedroom, she has the real baby.
