When Mary-Ellen lifts up John-Curtis to place the star on the Christmas tree, the star is flat and made of gold-coloured card. When the star is then shown atop the tree, it is 3D and made of silver-coloured metal.
When Jason returns home to tell John that there are no listed AWOL soldiers, the 'snow' on the ground is obviously cut-out pieces of white felt.
When Ike stands up to make a toast, he looks directly into the camera multiple times.
Although he's been on the run for awhile with likely no opportunity to shave, Paul has no beard or stubble.
When Paul carried Miss Emily's firewood into the house, the glass French door did not latch.
Chrome or foil hanging decorations clearly seen at the end of the story, did not appear, even in America until the 1950s. According to the Woolworth Museum the Wartime Christmas decorations were either natural, made of paper and folded to lay flat when sold or were make do and mend efforts.
When Jeffrey and the stranger share a muffin, the stranger is sitting with his back to, what appears to be, a redwood tree, which does not grow naturally on the U.S. east coast.