IMHO, that horse needs some serious re-training. He apparently cannot go around on a loose rein and she was having trouble controlling him in the canter. His body is all over the place and, frankly, he doesn't look even remotely enjoyable to ride. It looks to me like one big long fight
Their excuse is that it was his first show but IME, a horse with good basic training doesn't suddenly
start having such serious problems just because you added another horse around them while you were riding.