In the trial by combat, the Hound keeps destroying parts of his opponent's shield (one strike knocks off almost half the wooden facing), but the next moment it is still whole.
In Walk of Punishment (2013), Robb says that Willem and Martyn Lannister are Tywin's father's brother's great-grandsons. In this episode, Edmure says they are Tywin's nephews.
When Jorah Mormont and Barristan Selmy are riding, the sun changes position: in front of them when Barristan is speaking, and then, inexplicably, behind them when Jorah speaks.
When Jorah Mormont and Barristan Selmy are remounting their horses, a crew member's hand can be seen holding the far side of the black horse's bridle.
Beric Dondarrion says "Second time I've been killed by a Clegane." There is no mentioning in the show about the first time he was killed by the Mountain (in the novels, it happened during the Battle at the Mummer's Ford, which has been omitted from the show).