Plot hole: The prisoners fake a fire with some smoke bombs to have an excuse to rush into the print shop and smash up the print plates. Afterwards they even receive thanks and a reward for their valiant efforts. In reality, the guards would notice immediately that nothing in that room is even singed, but everything important has been smashed by fire axes.
Continuity mistake: As Stoffel sets off the smoke bombs, the first one lands by a set of silver cans by a crate. The second one lands in almost the same spot, but the first charge is gone.
Other mistake: When the head counterfeiter comes in, there is a sign on the barracks behind him that says "BARRACK 3." Two problems with this. First, Hogan and company are housed in Barrack 3. Second, there is not a Barrack building between Hogan's building and Klink's office building.
Revealing mistake: After the cell door blows, you can see the fuse of the stick of "dynamite" Newkirk placed still burning on the ground. Since the dynamite would blow when the fuse is burnt up, that literally can't happen. (00:22:40)
Visible crew/equipment: As Klink's car pulls up, and Klink comes around the front of it, the shadow of the camera is visible.
Is General Hammerschlag Burning? - S3-E11
Continuity mistake: As Hogan and Kinch walk into the club, Hogan is holding the mop up. A second later, it's on the floor, with his hand on top.
Factual error: While introducing himself to the downed Russian pilot, Hogan claims he is with the "US Air Force." He was actually with the United States Army Air Corps (USAAC) as the US Air Force wasn't formed until 1947, 2 years after the war ended.
Factual error: On the map in Klink's office, the nearest town's name is Hamilburg. This a misspelling, as the real name is Hammelburg.
Factual error: The guard delivering the Russian captive in the tunnel at the start of the show has a paratrooper M1 carbine with a bayonet lug. Bayonet lugs were not attached to M1 carbines until after the war.
An Evening of Generals - S3-E13
Continuity mistake: In Klink's office, the lower corner of the poster Hogan holds up alternates between being over the right side of his chest, to being tucked under, and back.
An Evening of Generals - S3-E13
Continuity mistake: In the barracks, after Hogan asks Newkirk about volunteering, the coffee cup Newkirk has is held with his left hand fingers in the handle. After the angle cut, the cup is in his hand with the handle toward the camera.
An Evening of Generals - S3-E13
Revealing mistake: The silver rack with bowls starts moving a second before the rocking explosion.
An Evening of Generals - S3-E13
Continuity mistake: As Klink is listening to Burkhalter, he is gesturing with a blue pencil. A second later, it's yellow.
An Evening of Generals - S3-E13
Continuity mistake: As Klink is listening to Burkhalter, his right hand is on the desk. A second later, it's at the top of his chest with his left, holding a pencil.
Everybody Loves a Snowman - S3-E14
Continuity mistake: Carter and Newkirk have just taken the escapees down the tree trunk to the tunnels. When they go to open it, they clear off the snow to open it. When the shot goes to a German soldier that was chasing them, the phony stump is suddenly covered over again. It would still have been visible, having just been exposed.
Everybody Loves a Snowman - S3-E14
Revealing mistake: As the sink with the fake tunnel is prepared, just before Newkirk goes over to set things up, you can see movement through a crack in the door. It's Schultz, Hochstetter, and Klink, waiting their cue to enter.
Everybody Loves a Snowman - S3-E14
Revealing mistake: When Hochstetter goes to open the snowman, you can see the plug is a poorly disguised piece of wood, as well as the piece of metal around the opening in the snowman.
Other mistake: The scene in Klink's quarters is one of a few where you can see Larry Hovis' (Carter) wedding ring.
Continuity mistake: After Hogan, LeBeau, and Newkirk leave, Carter is sitting, holding the glass with both hands. After the cut, he's holding the glass in his right hand only.
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