Revealing mistake: When Georgia walks into Billy's office naked, a triangle-lamp will cover her "naked" breasts. Look closely, for at one point you can see the white, strapless bra.
Pilot: The Spirit of Christmas (Jesus vs. Santa) - S1-E1
Revealing mistake: Each time Jesus turns his head to speak to the children when he is beating Santa Claus, he has two left arms.
Revealing mistake: When Alan serenades Jill, near the end of the song, the guitar player removes his hand from his guitar briefly but the guitar part continues to play (it's being synthesised as part of the keyboard's rhythm track). (00:19:10)
Revealing mistake: Whilst Bobby is reversing the truck before hitting the flagpole in Bill's yard we see the driveway in front of the truck. The very next shot shows Peggy from behind the truck instructing him how far to go to the flag pole and you can see they have used the same background as the shot before from the other angle. You can tell this as both shots are the same background as both angles despite from different viewpoints are exactly the same items and objects in both shots. Added to this there is a driveway in each shot, and Bill doesn't have 2 driveways in his backyard.
Revealing mistake: Right after TJ and friends are looking at the "thermometers" of cans, the Ashleys have at least 4 crates of cans that they bring in on forklifts. However, the end result is 4,362 cans for the Ashleys. This may seem kind of picky, but I think there was more cans than 4,362.
Suggested correction: This is literally just an assumption, and nothing else. 4,362 is a pretty huge number, and with the amount of cans that we see the Ashleys collect in the episode, combined with the amount of cans that they and the rest of Miss Furley's class collected off-screen, it is perfectly believable that Miss Furley's class would end up collecting that amount of cans.
Super Nova - S1-E2
Revealing mistake: When Stan, Xev and Kai are walking to the Memory Chamber, they seem to walk out of a two dimensional line at the lower left into the scene. The set and green screen weren't quite synched.
Revealing mistake: When the fashion club is looking at clothes in the store, Quinn and Stacy are looking in the mirror and their reflections properly show. When a slightly further angle is shown including Sandy (who stands right next to Quinn), Sandy's reflection does not show in the mirror at all (even though she's standing right by it). Also, no reflections are shown of any scenery in the store or the other two girls (who are within reflection range) - again, just Quinn and Stacy are reflected.
Working Guy - S2-E2
Revealing mistake: When Yvette and Floyd are playing basketball, the guys come home and distract him. Yvette makes some impressive shots, and you can tell that it's a stunt double because the hair is totally different. Yvette's is big and puffy, and the double's is long and straight. (00:08:15 - 00:09:40)
Revealing mistake: When Maya picks up Finch and slams him against the wall, you can see David Spade look down and step up onto an offscreen platform to give the illusion that Maya is holding him up. (00:13:35)