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.
Continuity mistake: A heavy rain is falling as Arlo and Spot are trapped in a rushing river. During close-ups of Arlo, the rain is falling at a sharp angle to the right. During close-ups of Spot, the rain is falling at a sharp angle to the left.
Continuity mistake: Arlo is surrounded by a large herd of gopher-like creatures. When they begin to crawl up his legs, he flings them off and begins to run. In the long shot which follows, the creatures are no longer close together but are scattered.
Chosen answer: It's a momentary emotional lapse. Arlo has come back changed, and his mother is seeing him differently now, as if he is his father.
raywest ★