The Informer - S1-E1
Visible crew/equipment: As Burkhalter looks down at the floor under the water tower, the studio lighting positions are distinguishable on the visor of his cap.
Revealing mistake: The film is flipped as the swastikas on the Gestapo uniforms of Hogan's men are reversed.
Six Lessons from Madame LaGrange - S5-E22
Character mistake: The SS guard salutes Major Hochstetter with his palm out, in the British fashion. Firstly, German soldiers salute palm-down, secondly, by the Wehrmacht (and SS) military protocol, he should just click his heels and not salute at all when receiving an order.
Factual error: About 10 minutes into the show, Newkirk is using binoculars to watch Klink put the combination into his safe. He goes one direction for the first number, the opposite direction for the second number, then goes in the same direction for third number. Opposite for the fourth number. For the radial tumblers to set, it has to be alternating directions.
Factual error: The program depicted WW2, 1939-1945 but several vehicles are 1947-48's.
Continuity mistake: Col. Klink is eating lunch. The meat on his plate moves from the left side to the right. (00:16:00 - 00:17:00)
German Bridge Is Falling Down - S1-E7
Continuity mistake: As Klink is talking to the sentry post, his hand goes from around the microphone part to along the length of the receiver between angles.
Other mistake: In the tunnel where the prisoners are storing ammunition. Col Hogan tells his men the next one that lights a cigarette gets a court martial. The tunnel is lit by open flames. (00:06:00)
Continuity mistake: Col Hogan eats Col Klink's chicken leg and places it back on the plate with meat still on the bone. When Col Klink picks up the chicken leg after, there is no meat on the bone. It's stripped bare. (00:01:00 - 00:03:00)
The Safecracker Suite - S1-E27
Continuity mistake: While Klink is talking to Hogan and the Major, the chair next to the door is almost centered under a picture frame. When the Major is arrested the chair is moved to the left. When Klink sits down, the chair is centered again. (00:03:50)
The Kommandant Dies at Dawn - S5-E6
Continuity mistake: As Schultz is eating from the tray he predominantly uses his left hand in each change of shot. When he takes the last piece, he has the toothpick in his left hand, when the shot changes he now has it in his right hand. (00:09:50)
Continuity mistake: As Hogan's telling Klink about the drawings, his left arm is extended. The next shot his arm is resting on the cigar box, then back to being extended and notice the pencil under the note pad. Next shot, arm is back on the box and pencil is gone. (00:04:45)
What Time Does the Balloon Go Up? - S3-E24
Plot hole: Hogan has the men fly kites to get wind data and build a hot air balloon for a man to escape in. In reality, kites and hot air balloons are pretty much mutually exclusive - if there's enough wind to fly kites, one can't launch a hot air balloon, and vice versa.
Revealing mistake: The first shot of the train the view is normal. Then after Lebeau starts in reverse you can see the smoke trail going in the wrong direction. The final shot shows the train moving in reverse, but notice the smoke trail is going to the rear of the train instead of the front as it should be, since it's moving in reverse. (00:15:05 - 00:22:25)
Factual error: Throughout the series, the SS and the Gestapo are often used interchangeably, as if the two organisations were basically the same. The most notorious example is "Major" Hochstetter, who sometimes claims to be Gestapo, sometimes SS, most of the time wearing an SS uniform. This is historically incorrect. The SS was a paramilitary and military organisation, while the Gestapo was a secret police force and since 1939 part of the Reichssicherheitshauptamt. The Gestapo, being essentially a plain clothes police, never had any uniform of their own.
Other mistake: As Schultz tries to find Flensheim on the wall map, what he's checking isn't a road map, but a city plan with a harbor on it.
Factual error: Towards the end of the episode, Burkhalter gets a call from a General Seidenbaum. Anybody with such a "Jewish" name would have been weeded out of the officer corps by the Nazis. In fact, anyone of that name would have had great trouble even getting his Ariernachweis (proof or aryan ancestry), and without carrying a copy with him he could not have opened a charge account at the local bakery. Most people with such names (those who managed to pass the Nazi board of racial review) had them changed to more "German" ones like Müller or Schmidt to escape the constant bullying. A little bit of background on "jewish" names: At some time during the medieval period, Jews in the German Reich who traditionally didn't use last names were forced to have them. Many selected names like Gruenbaum, Cornfield, etc. Which over time were perceived as "typical Jewish" names, even though many bearers weren't even of Jewish faith any more.
Six Lessons from Madame LaGrange - S5-E22
Factual error: Hilda is writing with her left hand. At the time of the Third Reich, it was still the practice in Germany to force left-handed children to learn to write with their right hand.
Factual error: In several episodes, German hand grenades, the famous "potato mashers" are seen. In (almost) all cases the Stielhandgranate 43, easily identified by its pull pin through the base of the head, was used. If the series is set in 42, the grenades should be the 24 or the 39 model, because the Stielhandgranate 43 - as the name suggests - was introduced in 1943 and didn't see widespread deployment until 1944. The earlier models didn't have a pull pin but used a pull cord that ran through the handle and was hidden by a screw cap at the end.
Visible crew/equipment: As the two German officers come out of Klink's office and approach the radar truck after Kinch leaves, the shadow of the cameraman, the camera, and the camera tripod are plainly visible on the left side of the scene on the ground.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.