When Danny gets shot at the end of the film, his paper flies out of his hand. But the very next shot of him shows that the paper is still in his hand being held over his head while he falls backwards. In one of the following shots the paper is back on the floor, but it's on the opposite side it should have been when it flew out of his hand. It's all shown in slow motion and it's very obvious.
The ending was originally different. After the scene where Derek is crying over Danny, it cut to Henry being arrested, then his family in the kitchen mourning him and saying he was a good boy, and then Derek shaving his head again while smiling. When Edward Norton read the script, he said "I thought the movie was supposed to be anti-Nazi." So the ending was soon changed.