Revealing mistake: LeBeau hands Schultz the pan straight from the hot plate, but Schultz puts at least three fingers around it while eating without any apparent issues. Note that LeBeau earlier said the Crepe Suzette were "not quite ready yet" - or in other words, still cooking. (00:01:40)
Continuity mistake: When Klink does a walk through in the barracks, he turns to face Hogan in front of Schultz. As he does, the end of his riding crop pushes against Schultz's lower chest and sticks. When the camera cuts the crop is free and well clear of Schultz.
Continuity mistake: Major Bonacelli goes to put his hand in his coat for money, he pauses with it in for the next few lines. When Newkirk asks about Germans eating a lot of pizza, Bonacelli's hand is suddenly out and gesturing.
Continuity mistake: Newkirk holds takes Schultz's rifle so Schultz can play in the game. On Schultz's second hit, you see Newkirk clapping. In the close up, you see Newkirk's hands firmly on the butt of the rifle. Also, Newkirk is holding the rifle with the muzzle in the dirt. This would put a plug of dirt into it, but when Klink takes it away, you can see that the muzzle is clean and clear.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.