The second time Kate goes to Tom's apartment The door is left a few inches ajar, in the next shot it is a few feet open, and in the final shot it's back to being a few inches open.
When questioning Santa and Kate after the break-in, right after one of them asks how to spell "ordinary", the police officers positions are reversed in the new camera angle.
Tom's top changes throughout the film. In one scene he is seen wearing a Grey top and a long tan coat. In the next scene his wearing a purple top a Grey hoodie and a tan coat.
The scar Kate shows to Tom is far too small to represent a status after a cardiac transplant. It should run over the breastbone from the top of the chest as the breastbone needs to be cut in the mid-line in order for the surgeon to open up the chest cavity and reach the heart. Earlier in the film when Kate sits at the table with her family she wears a low cut blouse and there is also no scar visible over the breastbone.
In 1999, young Kate is shown singing in Yugoslavia, which civil war had been reduced by that time to consist of Serbia and Montenegro. Kate says her family was from Croatia and had to escape from the civil war in Yugoslavia. However, fighting in Croatian territory and in adjacent Bosnia-Herzegovina ended in 1995. The only war fought in 1999 was at Kosovo, a territory within Serbia.
According to information displayed on the screen, the "present day" story is taking place in December 2017. However, the day and date displayed on Kate's phone regarding her audition appointment corresponds to December 2016, not 2017.
Tom supposedly lives in a one room studio. When Kate visits later with the Realtor a doorway is open and a staircase can be seen leading up to the second floor.
Kate and Tom go ice skating at Alexandra Palace and run away with their skates on to an alleyway in the West End of London. Alexandra Palace is approximately 6 miles away which would take around 2 hours to walk.