Other mistake: As the Telmarines advance out of the woods, there is a shot in which the mounted troops ride through a gap in the foot soldiers, then turn to line up in front. It is clear that this is a second take because the grass where the horsemen are about to ride is already trampled.
Revealing mistake: When Susan is in the forest and shoots her bow and arrow to hit the guy off his horse, the camera pans to the guy falling off his horse and the arrow can be seen still on the bow.
Chosen answer: Yes.
Disney-Freak