Continuity mistake: Elaine tells Jerry about the ex with the unclean bathroom. At the end she puts her lollipop in her mouth twice in two separate shots. (00:07:00)
Continuity mistake: George drinks from the bottle of anti-acid medicine, puts the lid back on, then at the "Yes, she wants me to like her" bit the lid is off again. (00:08:40)
Continuity mistake: When George shoos away everyone from The Apartment to make the phone call, in the background you can see the pink bottle with its black lid. When he actually approaches the phone, the bottle is uncapped. (00:09:35)
Continuity mistake: Jerry says he has never seen an episode of I Love Lucy in his life, then pops the cork on the wine bottle. Then it cuts to the lady and she asks, "Is there anything else about you I should know?" and the wine bottle is still on the table, corked. Then it cuts back to Jerry, and the bottle is still in his hand uncorked. (00:11:40)
Continuity mistake: During the scene with Donna and the wine bottle, besides continuity errors with cork and glasses position already mentioned in this page, the level of wine itself changes; Jerry poured wine to Donna, but her glass is empty in some shots, and before Kramer's arrival both are full, only to become empty in the last shot. (00:12:30 - 00:14:00)
Continuity mistake: Donna's purse strap changes position on The Couch throughout the scene, when she's there when George brings up her liking the commercial.
Continuity mistake: Kramer's moussed up hair looks much different in the first shot compared to the rest of the scene; it's way slicker and frizzles up right after the first cut. (00:00:55)
Continuity mistake: At Monk's, Jerry points at the woman feeding corned beef hash to her baby. There's an angle with the camera roughly behind Jerry Seinfeld's shoulder; the continuity here is sloppy, with George having his hand down flat on the table instead of with the fingers laced together with the other, and he has his right leg crossed and not the left. Just few seconds later he asks Jerry if he remembers his friend from Detroit, and he is pointing his left index finger at Jerry across the table instead, again, of having his hands close together. (00:07:30)
Continuity mistake: When Jerry's neighbours are arguing in the corridor about sponge size, Harold is holding the tiny scourer in different ways between shot (in a different spot and with his fingers suddenly stretched out). (00:08:40)
Other mistake: Jerry is at the party Elaine's friends have during the marathon. The clock in their living room never changes the displayed hour. (00:15:20 - 00:18:50)
The Statue - S2-E6
Continuity mistake: When Kramer gathers the old clothes, shoes, hat from the cardboard box on Jerry's table, they keep changing position in his arms between shots. (00:04:30)
The Statue - S2-E6
Continuity mistake: The first time we see Ray, he kisses his fiancée's hand. Elaine in that shot is holding her papers, with the thicker black book closest to her chest. A couple of shots later when he bows to "Jerry, lord of the manor" the books in Elaine's arms have switched position. (00:05:50)
The Statue - S2-E6
Continuity mistake: Jerry is on the phone with Rava's boyfriend to ask him about The Statue. In the close-up he is holding the cordless in his left hand, but the same hand is on his hip when he is in the background with all the others crowding the landline to listen. (00:12:30)
The Statue - S2-E6
Continuity mistake: During the scene at Monk's, Jerry bumps George on purpose making him spill some coffee. George is holding his cup in the right hand and the menu with the left. In the reverse shot you can see Jason Alexander put the cup down, held in his left hand. (00:14:20)
The Statue - S2-E6
Continuity mistake: George had enough of Ray's pawn shop story and jumps up calling him a thief. Watch the couple at the table; the woman, wearing a purple sweater, has her hand on the man's arm in the reaction shot, when nothing of the sort was happening in the wider angle. (00:15:30)
The Statue - S2-E6
Continuity mistake: In The Statue, George claims to have broken a statue that used to sit on his mantle. However, in season 6 episode 3 "The Pledge Drive", George states that he would be a completely different person if his parents had a mantle.
The Statue - S2-E6
Continuity mistake: Near the end of the episode, Kramer acts like a cop to get back The Statue. The door is almost completely closed. Just before he leaves, the door is suddenly open about one foot, even though it hasn't been touched yet.
The Revenge - S2-E7
Continuity mistake: George walked back into a meeting at his workplace pretending nothing happened. When his boss enters the room, George repeats in two separate the shots, differently, the gesture to hide his face behind a folder. The folder itself changed position before the boss arrived, since it was in his hand at first, then on the briefcase. (00:08:00)
The Revenge - S2-E7
Continuity mistake: During Elaine's amazingly off-putting flirting with George's boss, she starts mentioning how people don't say "Bless you" as they used to. She is gesturing with her right hand pointing a thumb -but before her "Have you noticed that?" is over, she is already in a new shot with hands joined and fingers entwined. (00:16:00)
Continuity mistake: George grabs the slip of paper from Elaine's hand. When he has his 'heart attack', in the shot when Jerry says "What does that mean?" the paper goes from his left hand to his right hand. (00:02:45)
Chosen answer: George does mention his brother in the episode "The Parking Space". They actually really never mention anything that contradicts the fact he had a brother though, it just isn't mentioned.