Revealing mistake: The waterfront set always features a blue, cloud-dotted sky, even when the streets are wet from supposed rain. And the clouds are static, never moving or changing, betraying the fact that they're part of a backdrop.
Barbary Coast (1975)
1 revealing mistake in show generally
Starring: William Shatner, Richard Kiel, Doug McClure, Dave Turner
Continuity mistake: Conchita slaps Cash across the left cheek, which he's rubbing as he returns to his office. In the next shot, as he comes through the door, he's rubbing his right cheek instead.