Character mistake: The old photo of Sylvia and her friend shows them in RAF uniform. Sam, who is a serving British Army officer and could be expected to recognise the very obvious differences between the uniforms, keeps referring to Sylvia being in the Army and Sylvia does not disagree with her.
Character mistake: The 'perfect' German postcard Rollin has written is full of mistakes: 1) The 'sie' must have a capital 'S' because it's a personal pronoun; 2) The only sentence stops in the middle and makes no sense; 3) The word 'Besten' has to be written without a capital because it's not a noun; 4) In Germany the house number stands after the street name, not before; 5) The streetname makes no sense. Too many mistakes for a so-called 'perfect' card. (00:04:40)
Character mistake: In the scene where Captain Sobel is inspecting the soldiers at the beginning of the episode, he goes up to Sergeant Lipton and notices something wrong with his chevrons. Well, in that part, Sergeant Lipton is not standing correctly in the position of attention because he is sort of slouching and his head is in front of his shoulders and the correct position of attention is standing straight up and having your neck behind your shoulders. If he was in the real army, he would have gotten a punishment for not standing at the correct position of attention. (00:09:30)
Character mistake: When Sav asks Ali if she wants people to think she's not good enough for their family, Ali accidentally calls Sav "Ray" when she responds: "Yes, Ray, that's exactly what I want." Raymond "Ray" Ablack is the name of the actor who plays Sav. (00:17:31)
Character mistake: In season 4 episode 13, "Tuesday," when Marshall is meeting with Ulrich, he is both able to understand and reply in German. In season 5 episode 15, "No Hard Feelings," Marshall almost misses the opportunity to change the street light from red to green, because the text is all in German. Jack has to tell Marshall which word is green, indicating that Marshall does not understand the German language.
Character mistake: When Walter is saying his father was a scientific pioneer at the university of Berlin, Peter reacts by saying: "Yeah, I know. Who came here in 1933, which is long before the Nazi's ever took power." In fact it is EXACTLY when the Nazi's took power: 30 January 1933. (00:19:00)
Character mistake: In the final episode, Carlos visits Doc in the psychiatric hospital for advice concerning his upcoming marriage to Holly. While talking, Carlos refers to Doc's deceased wife as "Linda", while throughout the series, it has been made very clear that her name was Deborah.
Character mistake: Dr. Agnes Jurati, one of the Federation leading scientists, is bored during the hyperspace travel, and so she chats a bit with the captain. While she gives her quirky speech, she casually mentions that "there are over 3 billion stars in our galaxy." She's not wrong, technically, but the number of stars in our galaxy is estimated between 100 and 400 billion. She is way off. (00:08:40)