The Burning - S9-E16
Continuity mistake: At the beginning of the episode, when Puddy is farewelling Elaine on the street, he is standing on the sidewalk and leaning through the driver's window. The following shot when she pulls out quickly, you can see through the windows of the car that Puddy is nowhere to be seen.
Continuity mistake: In the episode "The Suicide", Kramer discusses suicide with Jerry, and says that he'd give someone 72 hours to come out of a coma before all his property is up for grabs. However, in the episode "The Comeback", Kramer tells Jerry that he never knew that people could come out of a coma.
Continuity mistake: When "Mulva" is giving Jerry a neck massage, check out the bathroom door in the background. It keeps changing from open to closed.
The Slicer - S9-E7
Continuity mistake: When Elaine is woken up by her neighbor's alarm she looks at her own bedside alarm clock and it shows 3.30 AM. In the next shot when she buries her face in her pillow and screams, that clock shows 3.29 AM. (00:00:50)
The Library - S3-E5
Continuity mistake: When Bookman is lecturing Jerry in his apartment, he picks up a navy book with gold lettering and places it on the bookshelf in front of a pink book. For the rest of the shots, the navy book disappears and the pink book is back in front.
Continuity mistake: At the beginning of the show, when Jerry is having a massage, his hands are in front of him, under his chin. The position of his fingers change considerably after The Masseuse says, "I don't know" but then return to the original position in the next shot.
Continuity mistake: When Newman and the landlord look into Kramer's apartment through his peephole, the background doesn't match from when they look in and when he opens the door.
The Calzone - S7-E20
Continuity mistake: This mistake is in The Calzone episode. Towards the end when George walks in and his boss is looking around for the smell of calzones, George is holding a bag in his hand. In the next shot that shows the back of the boss's head the bag is now on top of a box that George is carrying. When it goes back to a close up the bag is in his hand again.
Continuity mistake: When George is lying on the floor in his underwear, a newspaper is on his right side. When they take the reverse shot (Jerry's view of him lying there), the newspaper is on George's left side.
Continuity mistake: When Morty is giving Jerry directions to the scuba diving site, The Pen alternates between being in Morty's hand and on the table between shots.
Continuity mistake: When Jerry's sitting with George in the hospital talking about George's jacket, as Jerry says "no, I tried it on, it fits good", he's gesturing with his left hand, which he then puts in his lap. From the reverse angle though, his left hand's still raised, then he lowers it again.
Continuity mistake: The bite size of the cookie that Jerry is eating changes between shots, without him even taking another bite. Not to mention the white and black change sides.
Continuity mistake: Jerry's apartment in the first episode was on the fourth floor. Then in the next bunch of episodes it was 3A. It then changes to 5A for the remainder of the series.
Continuity mistake: The private jet that The Limo pulls up to on the ground and the one that they show the gang on while flying are two different types of planes.
Continuity mistake: In the opening scene in the locker room, George's shoe goes from off his foot to on to off to on.
The Statue - S2-E6
Continuity mistake: In The Statue, George claims to have broken a statue that used to sit on his mantel. However, in season 6, episode 3, "The Pledge Drive," George states that he would be a completely different person if his parents had a mantel.
The Cigar Store Indian - S5-E10
Continuity mistake: George has sex in his parent's bed, explaining "My bed is too small." But in another episode, we see George's parents bedroom, and they sleep in separate twin beds, not a big bed.
Continuity mistake: Towards the end of the episode, it transitions between the Yankee ball at night and "Susie's" wake which is during the day.
Continuity mistake: In this episode, George asks Russell if his last name contains a "y" and Russel answers that it doesn't. However, Russel is credited in this and subsequent episodes as "Russell Dalrymple."
The Red Dot - S3-E12
Continuity mistake: After Elaine unwraps her cashmere sweater, Kramer wraps the ribbon around his neck in a scarf-like way and then lies back on The Couch. In a long shot of The Apartment (as Elaine exits the bathroom), the ribbon is gone, but when it cuts to Kramer and he asks about The Red Dot (and for the rest of the scene), the ribbon is back.