In the final scene on the porch, Andy finishes his pie, places the plate and fork on the side table, then turns to Aunt Bee. In the immediate wide shot, a cigarette has appeared, from nowhere, between his fingers.
When Fred Goss drops off Aunt Bee at her home, he is standing on the porch. As he turns to leave, he casts a shadow on the backdrop which appears to be only a few feet behind him, depicting her home, rendering the scene less than authentic. EDIT: What appears to be a backdrop is actually the front porch screen door.