The Night of the Plague - S4-E24
Other mistake: In the last fight scene, West runs uphill from the cave entering the scene from the most east side of the screen. There is a bad guy on the ground to West's right side as West is running uphill. The villains chase West, but their shot shows them entering the same scene from the middle of the screen with the guy on the ground on their left side.
The Night of the Pelican - S4-E13
Deliberate mistake: After Jeremy Pike drops the box in front of the firing squad and it begins to emit smoke, the wind blows the smoke to the right. The actors playing the soldiers in the firing squad then move themselves into the smoke and begin coughing and choking from it.
