Revealing mistake: When Sgt. Troy throws the grenade at the Gestapo agents barricaded behind the table, it is thrown wide right, yet the pyrotechnic explosion is dead center of the table barricade.
The Man Trap - S1-E2
Revealing mistake: Just after Kirk stuns Crater with his phaser, he gets up to get to Crater, when he does he bumps into a heavy stone monument,a prop that shakes visibly on contact. (00:36:58)
The U.N.C.L.E. Samurai Affair - S1-E27
Revealing mistake: Mark's stunt double in the final fight scene has a very bad (and obvious) brown wig. Mark's hair, however, is blond. (00:44:00)
Revealing mistake: When Briggs disguises himself as Rogosh's defense attorney, the glasses he puts on very obviously have no lenses in them. (00:26:05)
The Joker Goes to School (1) - S1-E15
Revealing mistake: Batman drives out of the batcave alone. The first bit of stock footage of the car leaving the cave does indeed show him alone in the batmobile. But the very next stock shot of the car speeding down the dirt road shows us Robin sitting in the passenger seat. (00:05:25)