In the final scene, the Hound stands before Ray, who is hanging from the partly built Sept. He turns to pick up an axe - but when he picks it up, Ray is no longer hanging from the Sept in the background.
When Sansa is writing the letter to send on a raven, she adds a red wax seal to the letter. However when she lifts the letter to examine it, the seal is gone.
Bronn tells Jaime "You promised me a lordship and a castle and a highborn beauty for a wife". Jaime promised him "a much better girl and a much better castle" in The House of Black and White (2015), but no lordship.
When Jon pleads with House Mormont for allegiance, Lyanna Mormont mispronounces Sansa's name as "Sandra."
Arya is left-handed, but in this episode she consistently uses her right hand.
When Black Walder holds a knife to Edmure's throat, during a closeup, the blade is revealed to be an obvious prop blade without an edge.
Between 6:36 to 6:42, the scene has a stream/river in the background. The stillness of water gives away that it's a backdrop.