One of the photographs that falls out of the music box is of Wednesday, Enid and Tyler in Tyler's car on their way to the Gates' home. There isn't enough time for the photo to be taken, developed and then placed in the home before they got there.
In Xavier's studio, Wednesday visits him to ask about the gate she has drawn. As the view pans around the room, the drawing of the monster's cave is clearly visible. Wednesday stole that drawing earlier; it should not be there anymore.
In the Eugene's hospital room, Wednesday is sitting with her backpack on the back of the chair. When Dr. Kinbott enters and Wednesday stands, the backpack is clearly still on the chair. A moment later Wednesday exits with the backpack suddenly on her back.
(At around 33 minutes) Wednesday's lips do not match her mouth movements for the line, "More seating for year-long Dia de los Muertos."
Enid calls her present to Wednesday a "snood". It is in fact a crocheted moebius cowl. A snood is a traditional piece of headwear for women, consisting of a band with a net or bag enclosing the full length of hair at their neck. The girls never wear these "snoods" in any manner but that of a scarf.