The guard at the bridge raises his arm and puts his hand on his chest but in the next scene it is by his side.
Benjamin Stahlbaum gives his children some presents to open but the eldest, Louise, objects that it's not Christmas Day - so he explains that these came from their mother, who asked to him to do this on Christmas Eve. However, in Victorian London it was Christmas Eve that was the traditional day for sharing family presents.
Upon learning that she is a princess, various soldiers address Clara as "Your Majesty" - but that rank applies to a queen, and she should have been addressed as "Your Highness".
When the automaton with three swans is going backwards, the sound heard is that of a recording played in reverse, which distorts every note - when in fact all the notes should sound perfectly normal, just being played in the wrong order.
Every decorated conifer has the same silhouette, with an identifiable bare patch on the left side of the trees, suggesting that the image was simply recycled once rendered. Real trees look different from each other.
Hawthorne queries what Christmas is, suggesting that the holiday doesn't exist within the four realms, yet within the four realms conifers are explicitly referred to as "Christmas trees" twice.