Revealing mistake: When Butterball is rolling down the hill in a snowball, he hits a tree and falls out. You can tell it is just a stuffed animal since there is a stitch on the top of his head.
Continuity mistake: When Adam and the puppies are racing just before they reach the first checkpoint, there is a wide shot and you can see that Rosebud is on Shasta's right side, but when we go to the close-up, Rosebud is on the left side, but when we're in the close-up just after Adam says "Great, no one's limping", Rosebud goes back to being on Shasta's right side.
Continuity mistake: In the scene where the Buddies are wondering how their kids are, we see the kids really upset about them not being home and we go to Alice trying to decide what to wear. In the next shot, the dresses she's holding change places.