When the caretaker gets out of her car with a bag of groceries, she has a carton of eggs in the bag. When she enters the house, there are two cartons.
The loose wire laying on the gravestone is not a telephone wire. The wording "type TW 600V"
can be seen printed on it. This is used for regular house current circuits of 110 or 220v.
When the characters are playing cards, the cards on the table change randomly depending on the shot, without any reasonable connection to the actual game and/or previous shot.
When Elva is sitting in her car at the cemetery, there's a man's face visible to the left of her head, reflected in one of the car windows, and then it's replaced by a hand twisting something. It is unclear what is being twisted, since the camera isn't moving at the time.