During the race, when Goofy throws the horseshoe at Brad, Brad falls down and his chin hits the button on the remote to set off the rocket skateboard. In the next shot of Brad when he's getting up, the remote is nowhere to be seen.
After Goofy crashes though the roof of the factory, it is revealed that the sunlight is shining through his shape in one shot, but when we see him get up from under the pile of toys, no sunlight is shining through.
When Goofy accidentally switches the conveyor to "fast", there is one shot where it's going not as much faster as shown in all shots.
When Goofy is asking Sylvia out on a date, his eyes are brown in a few frames.