The cars following Penny and Amy change between shots from a black SUV to a red compact sedan.
At 15 minutes, Penny and Amy are riding in a car, and their seatbelt-wearing status changes between shots.
When Penny is reading Sheldon's potty training journal, one journal in Sheldon's left hand keeps alternating between open and closed between shots.
When Sheldon interviews Alex, there is alternately (not) a gap in her bangs.
When Amy tries to call Sheldon and gets Alex instead, she holds the phone with her pointer finger folded behind it. But in close-ups, the tip of her finger sticks out from behind the phone.
Howard tells Bernadette that the Soyuz spacecraft meant to take him back to Earth has been delayed. In fact, International Space Station mission rules require that there must be a Soyuz docked with the ISS and available for the current crew at all times, in case they must abandon the station in an emergency.
Howard says that the Russians "left dogs up here in the 60s." This is untrue. In 1957, the Soviet Union sent ONE dog, Laika, into orbit with plans to euthanize her. The euthanasia failed and the dog died when the oxygen was used up. No other dogs were sent up and none were sent up in the 1960s.
Alex assures Sheldon she put half a teaspoon of rainbow sprinkles on his frozen yogurt. However, once the lid is lifted off no sprinkles are visible, only chopped nuts. Response: Rainbow sprinkles are visible on the yogurt, not nuts.
With his eidetic memory, Sheldon shouldn't have needed his mother to send him his old journals. Having someone else go through them didn't occur to him until he had them.