Clearance Sale at the Black Market - S4-E1
Character mistake: When Hogan addresses him, Major Kiegel sends the girls away from his table by saying "Raus!" The word "raus" used as an imperative literally means "out" in the sense of "leave the room" - he would be ordering the girls to leave the tavern, or at least the tap room in this case. It's not correct German to use it to send somebody away from a table.
Factual error: In several episodes, Hogan's men communicate by radio with a British submarine, and the dialog hints that the sub is submerged at the time. During the WWII era, submarines could not communicate by radio without surfacing first. In most episodes one might argue that the sub could be running shallow with a mast up, which would perhaps be within the technical possibilities of the era, but in this episode, the sub is talking to Hogan's men while under attack by a destroyer. This pretty much rules out running at periscope depth, because ramming was regularly-used tactic for killing subs that were in the process of diving or surfacing. To avoid confusion: Nowadays, subs can communicate while running several hundred feet deep by using VLF and ELF. However, these are definitely not capable of transmitting voice, but are text-only.
Audio problem: In several episodes, e.g. S1E31, German police sirens are heard to underline the impending arrival of Gestapo or other police officers. In each occurrence, the sample used has a distinct Doppler effect. Doppler effect in a sound occurs only if a vehicle passes by the listener at high speed, not when a vehicle approaches a place directly and stops.
Guess Who Came to Dinner? - S4-E9
Factual error: Schultz says, Von Grubner has "a castle right next to the Führer's in Berchtesgaden." Hitler's famous real estate in Obersalzberg wasn't a castle but a mountain chalet based on a former farm estate called the "Steinhaus".
Guess Who Came to Dinner? - S4-E9
Audio problem: When Hogan says "Why is it you can only trust short, dumpy spies?" the movement of his lips does not match the words.
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.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.