The Letter - S5-E7
Factual error: Sgt. Saunders is looking at a color photo of his kid brother in a letter from home. Aside from being prohibitively expensive for the average family to afford, color photos were not common. Also, the wartime rationing of photo chemicals for color film used by civilians would not be available.
The Letter - S5-E7
Revealing mistake: The same strawberry-blonde haired stuntman (Paul Busch) is used three times: first as an American G.I. being shot, then as a German soldier being shot, and again as another American G.I. being shot - all in the same battle scene.
The Letter - S5-E7
Continuity mistake: After an American soldier is shot in the back during the first battle scene, his body disappears a few shots later.