Audio problem: Towards the end Fraulein Rahm sends a child towards the Americans after pulling the pin on a grenade attached to him. He runs offscreen but no explosion is ever heard.
Suggested correction: So the grenade was (thankfully) a dud. Considering they were wearing paper uniforms, it isn't unreasonable to assume they didn't have the highest quality equipment.
Factual error: Russians and Americans never fought in the same battle against Germans.
Suggested correction: The film does not depict Russians and Americans fighting in the same battle. Jojo's friend, Yorki, tells him that America is coming from one direction and Russia from the other, but also says they are being attacked by China and Africa. He is a child and doesn't really know what is going on. We don't see any of the attackers until after the battle is over, at which point they all appear to be American.