The steering wheel of the car in which Joan Crawford and Diane Baker are riding is a dark color. When they get out of the car, a white steering wheel can be seen through the windshield.
Early in the film, the front page of a newspaper announcing Lucy Harbin's sentence to an insane asylum features a photo of her wearing a pair of earrings that she didn't purchase until her release 20 years later.
Dr. Anderson's car is much closer to the gate in the fence in front of the house when Carol looks out the window than he first parked it when arriving earlier in the day.
When Lucy commits a double ax murder at the beginning of the film, there is absolutely no blood on ax blade or blood splattering during her brutal attack.
There are several references to the Fields' farm being a dairy farm. However, the cattle in multiple scenes are obviously Black Angus beef cattle.
Leo is shown using a paintbrush to paint a black car white, but it's clear that the car is spray-painted white.