Deliberate mistake: When Prince Henry was sitting on the porch, there was snow accumulated all along the inner side of the railing - but the attached perpendicular boards (about 4" high) on the outside should have blocked snow, or that amount of snow, from accumulating there. (00:42:30)
Revealing mistake: The chalet was visible behind Emily when she was outside talking on the phone, but subsequent views of Emily showed her in front of a solid white background (mimicking snow) - indicating the use of a green (white?) screen. (00:13:34 - 00:13:56)
Continuity mistake: The amount of snow accumulated on the chalet's wraparound porch railing was higher when looking outside compared to external views, such as when Emily was outside talking on the phone with Becca. (00:13:35 - 00:15:05)