During the brawl with the Nazi gang, Martin suffers a pronounced bruise on his right cheek. However, the next day when Freya visits Martin and apologizes for the brawl the previous evening, there is no sign of a bruise on his face nor of a fight.
When Martin accompanies Freya up the stairs and to her door, she plants herself behind the half-open door while peeking out at Martin as he leaves. However, in the following cut when Martin walks toward her brothers' Nazi gang and a brawl breaks out, Freya is now considerably in front of the door and stairs.
When Otto, Erich, and his Nazi friends leave their home, the entrance door is closed. However, in the following cut, as Martin walks Freya toward the door, the door is now open.
After the tree that Martin has just chopped falls, he picks up his ax and starts walking. In the immediate cut, a St. Bernard is just behind him. However, in the previous shot of the fallen tree, which is a long shot, the dog isn't seen.
The famous book-burning that went on in Germany in 1933 did not happen until May 1933, while the movie is set in winter during January and February.
(at around 46 mins) A large tree is framed, two ax chops are heard, and the tree falls. As the camera pulls back to show the tree on the ground, the stump comes into the picture. It's clear the tree was cut by a saw and not an ax.
Although the story takes place in 1933, Margaret Sullavan's hairstyle and clothing are in the 1940 mode.