The Armstrongs' personal Christmas tree is comprised of at least three different trees. There is the tree that Lauren and James cut down at the Christmas tree farm, which is about a foot taller than James. The undecorated tree in the Armstrongs' mansion is obviously an artificial tree when one looks through it (the trunk of the tree has all the hallmarks of an artificial tree), and is only slightly taller than James i.e. shorter than the tree cut down in the field. And the tree when it is decorated is much fuller than the tree when it was undecorated.
When Maryam is just about to walk out of the Anderson mansion, she has boots on inside. As she steps outside onto the Jingle Bell doormat, she has heels on.
During the polo practice they are playing with a white ball, which is wrong for snow play, but the next cut shows the correct red ball that shows against the snow. Later, during the match, they are playing with the incorrect white ball. So it's a factual and continuity error.