Audio problem: The top of the coffee pot is on the basket rather than open, but we can hear the conversation.
Continuity mistake: As the general comes into Klink's office, Carter pours another cup of coffee, and starts to put the pot down. A second later, he's putting it down again.
Continuity mistake: During Carter's second meal, the napkin in his shirt comes loose and starts to fall. A second later, it's firmly in place in his shirt.
A Klink, a Bomb and a Short Fuse - S2-E8
Continuity mistake: Newkirk comes out of Klink's office with a code book, and passes it to Le Beau, who immediately holds it up and opens it. In the close up, Carter's hands bring up a book with a camera in it, and Le Beau brings the book out from his back and opens it again.
Request Permission to Escape - S1-E32
Continuity mistake: As Schultz starts to wet Klink, several big spots appear on the left of Schultz's jacket, then disappear a moment later.
How to Cook a German Goose by Radar - S1-E24
Continuity mistake: As Tillman starts to talk to Hogan, he places his hand on, then removes, it from, Hogan's arm. A second later, he repeats removing his hand.
Other mistake: After talking to the officers in the Höfbräu, the scene shifts to a closed business with Hogan talking to the waitress. As it shifts, the cameraman accidentally shakes the camera.
Continuity mistake: When Newkirk calls "Heil Hitler", everyone in the lobby salutes. A second later, in the closeup of Hogan and Newkirk, everyone's arms are suddenly back by their sides, much too quickly to be real.
Factual error: In this episode, the HofBrau (which should correctly be written "Hofbräu") is displaying a big red neon sign above its door. From 1939 on, air raid regulations throughout Germany strictly prohibited any unnecessary display of light at night. Any light visible from more than 500m away was considered a breach of air raid regulations.
The Great Brinksmeyer Robbery - S2-E18
Factual error: In the restaurant in Hammelburg, where Schultz discovers Hogan and Newkirk, there's an advertisement for "Brauerei der Jager, Stadt Wien." (Wien = Vienna) Vienna and Hammelburg are more than 500km apart, and if Hammelburg were near Düsseldorf, where the series puts it, it would be more like 700km. That's a bit far away for a brewery to advertise in the pre-globalisation era.
Is There a Doctor in the House? - S3-E18
Revealing mistake: As Carter blows into the bottom of the oven, the suds that hit Newkirk in the face come out in a thin stream on top, not out of the whole stovepipe.
Crittendon's Commandos - S5-E25
Character mistake: To have an excuse not to start up the truck motor, Schultz claims his driver's license has expired. German driver's licenses don't expire.
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.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.