Fast forward to the part in the movie where Pacha and Cuzco are looking at the model of Pacha's village for the first time. Then Cuzco slams his model of Cuzcotopia onto Pacha's model house, and the house flies into the air and Pacha catches it. Then Cuzco shoves Pacha's arm, and the model house falls and brakes. But towards the end of the movie after Cuzco turns back into a human and they're looking at the model village again, Pacha's still holding the model house again, and it's as good as new. This was no doubt, a slip up.