The Protege - S2-E6
Continuity mistake: When Sprague is practicing shooting for the second time, we see that Paladin has put up a new target with no holes in it. Sprague draws his revolver and fires three shots but the cut to the target shows 4 holes in the center. He then proceeds to fire the other 3 shots. (00:10:15)
Continuity mistake: Jan Clayton steps out of the wagon, hands the baby to her daughter, then she lights a broom, but right when the girl says "What are you doing?!", she starts setting fire to the wrong wagon, and the mistake is instantly corrected in the next 2 scenes. (00:40:00)
The Town That Wasn't There - S4-E3
Continuity mistake: John Astin, playing a homely sheep farmer, wears a large fake nose throughout the episode. But in the saloon meeting scene, where Beau introduces him to the townsfolk, the nose is conspicuously missing.