Deliberate mistake: Sport's voice is noticeably dubbed by a different actor in several scenes throughout the episode. Her voice inside Aunt T's house is the original audio track done by the child actor. During the other scenes, the voice is done by June Foray (uncredited).
Continuity mistake: Just before Sport and Jeb come back from their first visit with Aunt T, their parents are walking around the pool deck where it's fairly dry. But when the children come back, the area where they are helped out of the pool is suddenly very wet, probably from earlier takes.