Continuity mistake: At the end, while Hogan and Klink are talking, Hogan's right arm alternates between being up with a note in hand to down at his side between shots.
Other mistake: Carter said the plans and note were in the box that was supposed to contain a model of the Hindenburg. However, the box he's building out of has "STUKA" on the side.
Visible crew/equipment: When the radar truck comes into the camp, as it slows, you can see the lighting rigs for the cameras.
Will the Blue Baron Strike Again? - S4-E12
Continuity mistake: When Hogan is listening to Kinch, his overcoat is open. When camera cuts from him to Newkirk and Kinch and then back, Hogan's overcoat is shut.
Continuity mistake: In the lobby, Morrison has his gloves on, and never removes them. When he reacts to the gun shot, the gloves are gone.
Continuity mistake: Metsker never removes his right glove, as it is visible in all close ups. In the last wide shot, his glove is suddenly in his left hand.
The Return of Major Bonacelli - S4-E25
Continuity mistake: Klink poses for a picture in quarter profile of the right side of his face for Bonacelli, who is actually getting a shot of the guns. Later, you see the picture, and Klink is fully facing the camera.
Revealing mistake: While talking about Von Baler's daughter, Hogan is facing the building talking with Carter and Newkirk. Behind him is an open area of the camp. If you look, you can see that there is no guard in The Tower, no shadow of The Tower of the guard hut (the sun is behind them and Hogan), and the snow is piled up about three feet behind Hogan, suggesting that the background is a wall mural in the studio.
Clearance Sale at the Black Market - S4-E1
Revealing mistake: The Major goes to shoot out the light that the boys have turned on so Kinch can get the pictures. The first shot is angled too low to hit the bulb, but there is no impact on the front of the door's crosspiece; the smoke and dust comes from behind it. The second shot gets the bulb, but there is no muzzle flash, just sound. Also, there is no impact mark on the brick wall behind the bulb.
Clearance Sale at the Black Market - S4-E1
Continuity mistake: When Hogan is talking to Kiegel, Hogan's eyes are level as he looks across the table at Kiegel. After Kiegel says "Not good enough!", the camera cuts to a close up of Hogan, and he's now looking up as if the Major is standing. A moment later, the Major stands and leaves.
Color the Luftwaffe Red - S4-E8
Revealing mistake: When the truck with Hogan and company pulls up to the Luftwaffe HQ, the camera pans to the right to look at Klink getting out of the side car. When the camera cuts back to Hogan and company, they shake as if the truck just stopped, but it can be seen that the truck was stationary.
Color the Luftwaffe Red - S4-E8
Other mistake: The telephone booth located by the Luftwaffe HQ appears to be one of the London police boxes.
Man's Best Friend Is Not His Dog - S4-E6
Other mistake: When referring to the barracks, usually Klink will refer to the buildings by their numbers (Barracks 2, barracks 3, etc.). In this episode, he calls the building "Building G".
The Witness - S4-E23
Continuity mistake: In the beginning, the guys are listening in on Klink's office. The cup in front of Newkirk has four pencils in it. The colors from left to right are yellow, red, blue, and orange. After the camera cuts to Hogan and Kinch, the wide shot shows five pencils arranged yellow, black, blue, red, and orange.
Will the Real Colonel Klink Please Stand Up Against the Wall? - S4-E13
Audio problem: When Carter, dressed as Klink, approaches the staff car, Bruno the dog starts barking at him. Watch the dog's mouth. It doesn't match the noises at all.
Will the Real Colonel Klink Please Stand Up Against the Wall? - S4-E13
Visible crew/equipment: When Hogan opens the window, there is a reflection of the studio lighting on the top pane.
Revealing mistake: When Schultz is on the way out after giving the guys the news about the inspections and roll calls, you can plainly see that the background behind him is a matte painting. This is easy to spot because the building in the distance is lighter in color, and there are ripples in the fabric used.
Watch the Trains Go By - S4-E19
Visible crew/equipment: When Klink is by the fence acting busy and talking to Schultz, twice you can see the shadow of the camera on Klink's overcoat.
Who Stole My Copy of Mein Kampf? - S4-E16
Continuity mistake: When the staff car with Leslie Smyth-Beddoes pulls in, Hogan opens the window to see who it is. As you look past Hogan, instead of a daytime backdrop, there is a black backdrop, and the wooden shutters are lit up as if it were daytime.
Happy Birthday, Dear Hogan - S4-E26
Other mistake: Hogan returns to camp after meeting with the underground, after learning the Germans are setting a trap. Kinch went down in the tunnel to Radio London just before Hogan returned. Hogan asked the men, "Where's Kinch?" and he shouldn't send any messages. Since Kinch was in the tunnel, Hogan should have seen or heard Kinch in the tunnel using the radio. (00:07:50 - 00:10:45)
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.