Deliberate mistake: Some clothes were interchangeable from one character to another (or within a character over time), despite their obvious differences in sizes/body frames. Hazel, as a much heavier senior citizen, was still able to wear her "lucky" carnation pink coat that fit her 58 years earlier when she was a skinny young lady. Hazel was also able to switch coats with Margot, who had a much thinner body. The coat on Margot even looked form-fitting afterwards. Kip's tuxedo did not look too large on Griffin. (00:45:20 - 00:49:50)
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)
Deliberate mistake: "Mama's Home Cooking" - a wood frame building in 1850 - was on fire in multiple spots (though not yet engulfed). The townsfolk lined up to pass a bucket of water to douse the flames, which would be futile given how involved the fires were, but they were able to extinguish the fires and the wood frame building was largely intact and the boards did not look charred. The building should have been smoldering hot for some time, but Angel was able to sift through the rubble to salvage some items. (01:45:58 - 01:46:56)