Audio problem: When trapped underwater in the net at the Black Castle, Peter pulls out his knife from his small leather sheath underwater and we hear a metallic rasping sound which it should not make since it isn't scraping metal. (00:49:55)
Audio problem: Peter tells Wendy, John and Michael, "There are mermaids! Indians! Pirates!" We hear the children repeat, "Pirates!" but their mouths do not actually say it. (00:22:45)
Audio problem: Aunt Millicent checks on the sleeping children and in the shot outside the bedroom we hear the sound of her closing the door. However when she is startled by her true shadow we see the bedroom door has been left ajar. (00:14:30)
Audio problem: Wendy is tied to the mast on the Jolly Roger when Hook forces her to tell a story. In the wide shot, the pirates start to find seats and Hook has his hand at Wendy's throat as we hear her begin, "There was a boy named Peter Pan," yet her mouth does not move. She continues to say off camera, "who decided not to grow up," and in the next shot Hook gets angry and tells her to skip the prologue. (01:18:00)
Answer: It's not that you never age, it's that you never grow up, i.e. pass into puberty and become an adult.
Myridon