Other mistake: At the end, on the steps in front of Stella's apartment, Stella's daughter stares at the camera for half the shot.
Other mistake: At the start of the episode it can be seen that the DVD player only has a power cord connected. Shortly afterwards only one cable (power) is seen connected to the TV set, then a few seconds later Ted plays a DVD.
Chosen answer: In a flash forward scene in Season 8, it shows him with his first born: a daughter.
XIII