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: The scene which George arrives at Beth's apartment in a messy condition to admit his remark was in jest, his shirt's hem and collar change between shots. During this scene, especially when he talks to Jerry on the phone, his collar is up and down; his hem is in and out of his trousers.
Continuity mistake: When George is at Susan's cousins' house complaining about them stealing the name Seven, its bright Daylight out. You can tell because the sun is pouring in through the windows. The woman goes into labor and they all get into the car to go to the hospital. At this point it is nighttime. When they finally arrive at the hospital it is broad daylight again.
Continuity mistake: In the start of the scene when Kramer tells Elaine that the armoire got stolen. When Elaine walks in from the right side she walks right past the armoire, and it still has the two blue straps on it so it's the same one. The gaffe seems to have been edited out in some versions.