Princess Flavia gives Rassendyll a red rose in the garden. As it lies on a book a little while later, it is white.
Rudolph's hairstyle changes when he is on the terrace with Flavia. In the brief dialogue with Zapt, his hair is longer and swept back. Presumably this part of the scene had to be re-shot a few weeks later.
While the King and Rassendyll toast their ancestors in the King's hunting lodge, the inebriated Fritz von Tarlenheim is so drunk that he is almost asleep. Every so often, he pops in with the word, "Toast!" The fourth time he says it, his mouth doesn't move.
In the opening credits, the Englishman's name is spelled Rudolf. In Michael's deposition proclamation, the king's name is spelled Rudolph. Antoinette's note to the Englishman is addressed Rudolf. On the wall poster at the railway station the king's name is spelled Rudolph. But when the Englishman overwrites the Ball invitation to Flavia, he spells it Rudolf, his own spelling and not the king's. She would have been surprised to think the king couldn't spell his own name.