When Lucy and George say goodbye while walking down the street, Lucy's hair is pulled behind her neck. In closeup, as she watches George leave, her hair is in ringlets hanging in front of shoulders, then reverts to the original hairdo when she goes into the pharmacy.
When Eugene and Lucy leave the Amberson mansion after the big party and drive away in the Morgan automobile, the top of the painted "trees" backdrop can then be seen at the top of the frame for most of the shot as they drive away.
Tim Holt and Anne Baxter walk past a nickelodeon movie theater advertising a film starring Jack Holt, Tim's father. However, the scene takes place a considerable amount of time earlier than that in which Jack Holt began his career in silent films (1914).
Towards the end of a long tracking shot with George and Lucy in a horse-drawn carriage, a portion of the rear end of a camera car and some sort of filmmaking equipment briefly enter the left side of frame.