Revealing mistake: When Laura picks up Baby Rose from Thomas Stark, the blanket is flipped up and you can see a plastic doll's leg, then when she goes into the bedroom, she has the real baby.
Revealing mistake: The actor that played Barney Miller, Hal Linden, was left handed and did everything left handed. However, they always put his gun on his right hip with the handle facing the right. A lefty cannot conveniently pull the gun this way.
Suggested correction: Hal Linden writes with his left hand, however he uses his right for many things. He ate with his right hand (in Graft), and in the episode where Fish thinks he needs to retire, Barney pulls his gun with his right hand.
The Countess - S1-E4
Revealing mistake: When the car falls off a cliff at the end, it's an entirely different looking model with different headlights (square vs round), and empty (at least nobody in the passenger seat for sure). (00:46:30)
Revealing mistake: When Major Popov aims the rocket launcher at the Venus probe, there is no rocket in the launcher- it is just an empty tube.