When Mannix is talking to Marty on the football field, in the wide shot, Mannix's hair is being blown around by the wind and is clearly out of place as a clump of it is sticking up in the air. But when the camera switches to a closeup shot of Mannix, his hair is neatly combed with none of it being blown around or out of place. The sequence is then repeated - the camera switches to a wide shot again where his hair is being blown around and is out of place and then switches to the closeup again where is hair is neatly combed and none of it is out of place.
The drawing that Mannix carries to the hospital and to Marty's place is not the same as the drawing the sketch artist drew. Notably, the dark shading to define the suspect's left cheekbone is not as well-defined.
When Mannix is talking to Augie about meeting him in the alley, a blonde waitress can be seen at the other end of the bar, but she disappears and reappears from shot-to-shot.
When Marty is talking to Mannix about the hole in his gas tank he says two conflicting things. First he says that the hole was as big around as a little finger, but then he says they think it was made by something thin, like an awl or an ice pick. Something that thin wouldn't have made a hole the size Marty said it did. What's more, if the hole were in fact as big around as a finger, then he would have lost fuel very quickly, especially since a lot would have been wasted while the car was sitting in the parking lot. It doesn't seem likely Marty would have been able to drive very far with a hole that big in his tank.
The futuristic clock of "The Odd Couple" s3 ep22 aired 3/9/73 is seen in the background of this "Mannix" s7 ep8 aired 11/9/73.
When Art is talking to Mannix he says that Tolan must be a pro as he didn't leave any finger prints. But when he was seen inside the apartment, he wasn't wearing any gloves, and he would have left a lot of finger prints everywhere.