In a previous shot, when Paul Anders runs Mannix off the road, Anders' car makes a dent in Mannix's car door. When Mannix's car comes to a stop, there is no dent in the door. The dent is now over the rear wheel and it is a different size and shape.
When Paul Anders is trying to run Mannix off the road, before he bumps Mannix's car, a dent can be seen in Mannix's car door, presumably from a previous take. When Anders' car makes contact with Mannix's, the bumper fits perfectly in the dent.
When Mannix and Althea Blake enter Paul Anders' house and she switches the light on, the click of the light switch is heard a fraction of a second after the light comes on.