I found this blooper in the movie when I was rethinking about it, after watching the movie. When John recieved the coin after purchasing his icecream, I recalled his dad washing the coin under the running tap. At this point of the movie both characters were young. Afterwards when him and his dad decided to go to the stores to learn more about this so called "mule" coin, his dad suddenly turns older to his present age in the movie (when John meets Savannah). Yet, John was still in his childhood age.