In the montage of the show tour around the USA, the same city set is used for Cleveland and Washington DC without even bothering to change the shop signs: "Century Antique Shop" and "Yvonne Milliner" are visible in both "cities".
The uniform worn by Gertrude Niesen in the opening sequence is strictly of a 1943, not 1917, design, complete with padded shoulders and knee length skirt, and totally inappropriate to the 1917 era.
The map showing the German attack on Poland on September 1, 1939 shows the Austrian-Czech border from 1937.
During the "God Bless America" sequence, Kate Smith barrels up to the microphone and her dubbed-in voice is heard to say "It is my happy privilege to introduce a new song: 'God Bless America'" If you read her lips, however, she actually says the words "new tune."
President Franklin D. Roosevelt is depicted as walking and standing despite being confined to a wheelchair in real life.
At 48.22 the fifth soldier from the left, bottom row sits up and turns his head before the rest of the cast. He slowly straightens his head then turns right in unison with the rest of the cast.