Do you mean Jack Webb's Project UFO, which was a dramatization of Project Blue Book investigations? As I recall, they typically covered 2-3 cases per episode, and the standard formula was that at least one was debunked as a hoax while one was left ambiguous. But that's not quite the same as the kind of formula I'm talking about, where the episode is about one specific thing that's proven to be a hoax, but then there's just this brief moment before the final freeze-frame that either hints or confirms that it was real all along. (Like the episode of The Greatest American Hero where Ralph tries to prove a plesiosaur cryptid is responsible for the Bermuda Triangle disappearances, and it turns out to be pirates hijacking boats, but in the end, the heroes sail away and don't see the cheesy rubber monster head rising up and mugging into the camera.)