A Musty Crypt and a Stick to Pee On - S4-E5
Revealing mistake: When Georgie is imagining what it's like to be a father Jana is shown holding two babies in her arms. You can tell that the babies aren't real they are just dolls.
Freshman Orientation and the Inventor of the Zipper - S4-E6
Plot hole: Memaw gets a call from Dr. Sturgis saying that he has moved to Waxahatchie and would she please call him back. He does not say the new phone number, and this was well before cell phones were in widespread use by the general public, so it could only be a land line. Memaw calls him back, although she could not know the number.
Answer: Some people just have a dislike for someone that can't be explained. Could be as simple as the way he's dressed.