Hogan's Trucking Service... We Deliver the Factory to You - S4-E4
Deliberate mistake: When Schultz drives off with the motorcycle leaving the sidecar behind, you can see that the sidecar has been propped up. It has to be, or it would fall over. Sidecars, bringing only one wheel to the party themselves, can't stand up on their own.
That's No Lady, That's My Spy - S6-E17
Factual error: Hogan tells Carter that the bush he's camouflaging himself with is poison ivy. Poison ivy is not native to Germany, the very few wild plants that exist today descend from those introduced to botanical parks after 1942.
Other mistake: The place the car ends up on the porch is where the wooden steps would have been. But there is no debris from the destroyed steps, meaning they were removed for the gag.
Other mistake: As the camera looks at the now-crashed car, the position and condition it is in is impossible. Though funny, there is no way the car could have jumped up on the porch as shown. The front would have been crushed in, the wood of the porch damaged. The interiors of the doors are impossible given that the car would have been kept in an immaculate condition.
Revealing mistake: As the camera looks at Schultz driving the car, even though he's moving in the seat, you can see through the back glass the car isn't moving at all.
Visible crew/equipment: As Schultz drives away from the boys, the camera crew and equipment is reflected in the window.
Visible crew/equipment: As Schultz looks at the prisoners after being told of the escape, the studio lighting rig is reflected on his monocle.
Visible crew/equipment: As the man gets in the passenger side of the car after the agreement is signed, the studio lighting rig is reflected in the glass.
The Experts - S6-E2
Character mistake: At the end, Klink goes to drive away, saying "Dismissed" to Schultz and Hogan. As he does, he salutes. This is wrong as Schultz should have saluted first.
Continuity mistake: As in S5: Ep1 "Hogan Goes Hollywood", the bridge Hogan looks at through binoculars is vastly different than the one wired with explosives. When the bridge blows up, it is a re-use of the footage from earlier episodes.
Continuity mistake: Even though Carter pops his head out of the hatch to talk to Hogan, it isn't Carter that's seen in the window as the tank approaches Hogan's position.
Visible crew/equipment: As Klink and Schultz approach the barracks where Le Beau is "weightlifting", there is a cord or cable along the ground that would be for studio equipment.
Continuity mistake: As Schultz takes the balloons away from Hogan, Newkirk is nowhere to be seen. A second later, he witnesses the entire scene.
Continuity mistake: As Klink asks about the forecast, his hand is around the microphone end of the receiver, then a moment later it's around the handle.
Continuity mistake: As the men are lined up, Klink starts to grill Hogan. Klink has his pistol aimed directly at Hogan, then it's at a 35 degree angle toward and close to Hogan's face. A moment later it's about two feet away from his face.
Continuity mistake: In Room 210, Newkirk's sleeves are down to his wrists, but in the close up of his hands, the sleeves are totally missing.
Visible crew/equipment: As the car with the kidnapped Klink takes off, the Stalag 13 buildings are reflected in the windows, along with the camera equipment and lighting. (00:01:20)
Will the Blue Baron Strike Again? - S4-E12
Continuity mistake: The cigar Hogan takes from Klink goes from green to light brown when starts to name the top invitees to the party.
Continuity mistake: As the ambulance leaves the hotel, there is snow on top of the fenders and spare tire. Back at the truck, there is snow on the fenders, but not the spare. This would be impossible as at the speed driven, the snow would have blown off any horizontal surface.
Continuity mistake: As Hogan, Carter, and Newkirk go to get out of the Army truck, the ambulance doors are wide open. As Hogan walks by, the doors are straight out toward the truck.
Answer: Nimrod's actual identity was never revealed in the series. It was only known that he was a British intelligence agent. Nimrod was not Colonel Klink. Hogan had only implied it was him as a ruse to get Klink returned as camp commandant, not wanting him replaced by someone more competent who would impede the Heroes war activities. The term "nimrod" is also slang for a nerdy, doofus type of person, though it's unclear why that was his code name.
raywest ★
"Nimrod" is originally a king and hero mentioned in the Tanach and taken into the Bible and the Koran. His name is often used in the sense of "stalker," "hunter," and sometimes figuratively as "womanizer" as in "hunter of women." I've never seen it used to denote a nerdy person, and although I cannot disprove that connotation, I think given his role, the traditional meaning is more likely the intended one.
Doc ★
It's widespread enough that Wikipedia has an entire section on it: https://en.wikipedia.org/wiki/Nimrod#In_popular_culture