The robbers while on the beach are all wearing jackets, yet the skin diver is wearing only swim trunks. If it were cool enough for jackets, the diver would wear a wetsuit. With an air date in February 1956, it was filmed in the winter of 1955, so the apparel of the robbers was correct.
The highway patrolman calls the dispatcher to get a make on the robbers car. The dispatcher comes back with a description of a 1953 car. The robbers car was a 1956 Dodge.
When unit 1430 calls Matthews to alert him that the robbers car turned off the road, he keys the microphone and holds the button too long after he finishes talking- Matthews is heard saying "Proceed with caution" while the transmit button is still being held down. Since police radios of that era were only able to transmit or receive at one time, this indicates the sound of Matthews talking was added after the scene was shot. This error is repeated when 1430 calls Matthews to tell him he lost the robbers car and again when he calls in having located the robbers car. He holds down the transmit button during the entire conversation.
As Mathews and the sergeant, played by John Hart, stand at the map, it's obvious that it's a map of Los Angeles [in the 1950s], complete with the Pacific ocean on its left. Yet, during the series, assorted dialogue makes clear that they're not in California.
Shadow on wall at 15:14 as Dan is getting up from his chair.
Matthews improperly handles items of evidence such as the cup and food container by placing his own fingerprints on them and possibly covering any existing prints.