Óscar Torres, the man on whom the story is based, was on set for most of the shoot. He was often seen crying between takes off set, saying the shots brought back painful memories.
The American staff sergeant's rank switches from the correct position (chevrons up) to an incorrect position (chevrons down), back to the correct one when the cameras change in one of the scenes.
The candles on Chava's birthday cake form an arc of 270 degrees (3/4 of a circle) in a close up and then they are shown placed in a complete circle in subsequent wide shots.