Continuity mistake: In the scene where Steph is in her second show, there are at least 2 different horses. The manes and tails go from being braided to being unbraided. Also, the breeches change from grey to beige. One of the horses before her round, a chestnut, has one sock, then none, then three, etc. There were multiple (I counted at least 7) horses that played the part of Lightning, who was supposed to be registered with the Jockey Club, which is the Thoroughbred registry. Most of the horses that played him were not even close to being Thoroughbreds.
Continuity mistake: Fallon said he was not a race horse...then why is he registered with the Jockey Club? Even if he had never raced, he still would have been bred for speed if he was registered with the JC.
Continuity mistake: If Lightning was as expensive as everyone said he was, why would Fallon trust a girl he didn't even know with such a horse, let alone jump him?