Every Bundy Has a Birthday - S7-E3
Revealing mistake: At the park when Al hits the rich man, he goes down like he was knocked out. Soon after, Seven punches the kid. In the background the rich man is actually sitting up on his side and he looks at Al and Seven, then as the camera pans towards him, he lies down on his side like he is passed out again.
Kelly Doesn't Live Here Anymore - S7-E8
Revealing mistake: You can plainly tell that Kelly is wearing a beehive wig at the diner when Peg comes and talks to her.
Revealing mistake: Kelly is making popcorn on the stove. It starts popping even though the heat isn't even on.
Revealing mistake: The burglar uses a crow bar to open the sliding glass door. You can plainly see him "pretending" he had to use it when it just opens easily. He didn't really pry it open.
Movie Show - S7-E21
Revealing mistake: When everyone is standing at the snack bar eating all the food you can plainly see all the candy boxes are empty and already open even though they were sealed when the cashier put them on the counter.
Movie Show - S7-E21
Revealing mistake: When Kelly is eating the boxes of candy you can plainly see they are empty, but she's chewing anyway.
Answer: Bud's date is a foreign exchange student and Kelly was wondering what was sent to the country Monique was from in exchange for Monique being sent to America.