Continuity mistake: Whenever young Riley is pulling the wagon around the house, Fear stops her at a white cord in an outlet. In the next shot, it is a black cord.
Continuity mistake: Spot finds four other humanlike creatures and goes to them. Arlo is standing several feet in front of them. He begins to push some dirt by using his nose. A close-up then shows him using his nose to draw a circle around the five others but he is standing much too far away to be able to do this.