Sue Shelby offers Marty a cookie, and it appears to be whole. After he rejects the offer, she takes a bite, but there is a clear second bite in the cookie - as though the same cookie had been used in another take of the shot.
In the previous shot where the cookie is shown, it is whole.
In the previous shot where the cookie is shown, it is whole.
When Marty and Wendy arrive at the Kentucky horse farm, the viewer sees it surrounded by forests full of longleaf pine trees. There are no longleaf pine trees in Kentucky (filmed in Georgia where the trees are found).