Kramer's apartment number is usually 5B. But in this episode, when Jerry closes the door after his parents come back up, you can see that Kramer's apartment number is 3B.
When Manya first hears about the horses, her hands are on the table. In the next shot, her head is resting on one hand.
When Jerry is first apologizing for his comments about the horse, he leans forward. In the next shot, he is sitting up straight and starts to lean forward again.
At the coffee shop, there is a close-up of George talking and his hands are not visible. It then cuts to a different angle and one hand is touching his face.
When Morty sits on the couch with the remote on his chest, his hands are folded together, then suddenly resting at his sides.
During the coffee shop scene with Elaine, Jerry, and George, other than when Jerry picks up the silver cup, the cup's position changes on the table throughout the scene, including appearing and disappearing.
At the end, while Jerry, George, and Elaine are at the dinner, Elaine laughs at a remark from Jerry - "Who would have thought an immigrant owned a pony." Her laughing was clearly not part of the scene.