Seinfeld (1990) - 5 mistakes in series 4

Continuity: 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."

Factual error: In the scene where Jerry and Marla are making out on his couch, at the top right window you briefly notice someone walking by. This is impossible because the apartment that Jerry lives in is on the fifth floor.

Continuity: When Jerry and Elaine are in the coffee shop, a coffee mug can be seen in front of Jerry. When Gail enters, the coffee mug disappears and reappears between shots.

Factual error: Kramer gives Jerry a two-line phone for his birthday, which Jerry plugs in and immediately uses. But a two-line phone requires the installation of an actual additional phone line. What Jerry was using when the NYU reporter overheard him "admitting" he was gay was simply call-waiting.

Continuity: When "Mulva" is giving Jerry a neck massage, check out the bathroom door in the background. It keeps changing from open to closed.