To Russia with Love (1) - S3-E24
Character mistake: While talking with Falcon, Harm mentions the "green book" Falcon stole that listed all of the American POWs transferred to Russia after the Vietnam War. But when Harm originally found the book in "Ghost Ship", its cover was yellow.
Continuity mistake: Bud tells Harm that he was 11 years old when he took his first 'Tiger' cruise on the USS Arleigh Burke. However, the Arleigh Burke (DDG-51) was commissioned in 1991, which means Bud would only be 18 years old at the time of this episode.
Continuity mistake: When the Cubans prepare to fire the Harpoon missile there is a shot of the Mk13 launcher preparing the missile for firing. However, later in the episode when they fire, the shot shows the missile coming out of the vertical launch cells forward of the Mk 13 launcher.
Blind Side - S3-E4
Continuity mistake: In the bar the camera pans down to Harm's boots. He's wearing black jeans. In the jeep, when he jumps out to stand next to Mac, he has on light blue jeans.
Factual error: The coast guard officer on the bridge in the opening scenes is wearing the gold oak leaves of a LCDR but the gold trim on his hat indicates he is a full commander. Later in the episode he is identified as a full commander but is not called Sir by Harm or Mac. In reality, as a senior member of a US uniformed service, he would be called Sir.
Factual error: This episode begins with a luxury cruiser being pursued by a USN Oliver Hazard Perry class frigate. In order to convince the vessel to heave to, the skipper of the USN ship orders two warning shots to be fired from the frigates forward gun. Oliver Hazard Perry class frigates do not have a forward gun. They have a launcher, which is visible in the ships external shots. The shot of the 5" gun firing is archive footage of a completely different (and much larger) vessel.
Death Watch - S3-E19
Continuity mistake: At Harm's apartment, when talking to Mac about Cmdr. Krennick's advances towards him, he tells Mac that he wouldn't get involved with a superior officer, anymore than she would. However, it had already been established earlier this season in "For The Good of the Service" that Mac had a romantic relation with her Commanding Officer, Lt. Colonel Farrow.
Factual error: In this episode there is continual reference to the seahawk helicopter in the hanger. The helo that is pictured in the episode is a lot bigger than a seahawk and resembles a sea king. Oliver Hazard Perry class frigates can hold two seahawks but no Sea Kings.
Continuity mistake: The aircraft carrier used in this episode, the USS Coral Sea, had the correct hull number on the ballcaps worn by the crew - CV-43, but the hull number displayed on the ship was "65". CVN-65 is in reality, the USS Enterprise.