When Jonathan, Alex, his grandfather and Lista meet by the river, the moon is full, but it was only three-quarters full the night before. However, this could have been a creative choice by the filmmakers to show that "everything is illuminated" in that scene.
In front of the train station, Jonathan explains to Alex that he is distressed by dogs as Alex gets into the vehicle. Jonathan miraculously ends up in the vehicle after both the driver and passenger are seated in a 2-door Trabant.
Francis Scott Key is credited for the "Star Spangled Banner". The composer, John Stafford Smith (1750-1836), should have been given credit rather than Key who was the lyricist. In the movie, the performance is played by a band and no lyrics are heard.
In the movie it is stated that the townspeople of Trachimbrod were murdered by Germans, while in fact the murderers were mostly Ukrainians with small Germans contingent. Source: sztetl.org.pl/en/article/zofiowka/5,history/
When Alex's grandfather asks Alex and Jonathan to leave, Jonathan immediately leaves, even though Alex has not translated the request into English. This, however, was most likely a creative choice to show the power and emotion of Alex's grandfather's words.