When the family boards the boat, the bow and stern of the boat are tied to the dock. Cousin Eddie unties the line from the stern; in the next shot, the boat takes off and the bow line has disappeared.
When the family is on the fishing boat being pulled by a shark, Muka Laka Miki is holding/not holding Third between shots.
During Eddie's "poor me" scene in the living room after losing his job, he looks behind him at the dog lying on the loveseat with two throw pillows. Immediately afterward, Eddie flops himself down on the same loveseat but it is empty and a purple blanket has appeared and is hanging over the back of it. The throw pillows have vanished and the dog is lying on the floor under the Christmas tree in the other room.
When Eddie is keeping the signal fire going, a boat is visible offshore that looks like the one they arrived on, but soon after they're rescued and told that the same boat was found 300 miles away.
While Eddie is flying the float plane, shots of the instrument panel show the airspeed as zero, with fixed altitude, even during landing.
When Eddie looks out the plane window, he says the people look like ants. Third replies that they are ants, because the plane hasn't taken off yet. However, the weather is cold and quite snowy, and it would be impossible for ants to be active.