Revealing mistake: S9 E1 "Bully for Ben": When Ben hits the punch bag sideways, it's easy to tell that someone is controlling the punch bag as it never slows down.
Revealing mistake: In the shot where Suzie lands on the sponge cakes, the safety mattress under the cakes briefly jumps into the frame.
Revealing mistake: While Rory and Lorelai are in the kitchen, in a few closeups of Rory we see the refrigerator and counter area with the microwave, etc. behind Rory, but when Lorelai is at the back door about to join Luke, part of the set beside the refrigerator is gone. (00:04:15)
Close Encounters of the Beans Kind - S3-E8
Revealing mistake: When Louis and Beans fall from the sky on the bike, if you look carefully, you will see that they're both dummies.