The area around King's Landing is visibly different than shown before: the capital now seems to be located on a flat, desert plateau in both wide and close-up shots, where earlier it was surrounded by rocky hills and forest.
Tyrion and Qyburn talk at the gates of King's Landing, and then Tyrion walks around Qyburn to talk directly to Cersei (standing atop the wall). The gates do not open again, but Qyburn disappears from the scene. He is nowhere to be seen in any of the long shots (as Danerys and Grey Worm look at Missandei on the wall). Qyburn has simply disappeared.
Jaime claims "I strangled my cousin with my own hands just to get back to Cersei," referring to the murder of Alton Lannister in A Man Without Honor (2012). Actually, Jaime did not strangle but beat Alton to death.
When Brienne disrobes to have sex with Jaime, no claw marks appear around her neck. She should have scars from being clawed by the bear in The Bear and the Maiden Fair (2013).
There are three errors in Gendry's statement "I'm not Gendry Rivers anymore": first, no one has ever addressed him as "Gendry Rivers" in the show, only as "Gendry." Second, the special surname is given only to bastards who are noble-born and that their noble parent has acknowledged them openly; Robert has never acknowledged Gendry as his son. In fact, Gendry was unaware that Robert was his father until Melisandre told him that in The Bear and the Maiden Fair (2013), long after Robert's death. Third, the special surname is given according to the region in which the bastard in question was born (in the North - Snow, in Dorne - Sand, etc.). Had Gendry been acknowledged by Robert, his surname would have been "Waters", not "Rivers", because he was born in the Crownlands, not in the Riverlands.
After Rhaegal is killed by the scorpion crossbows, those same crossbows fire on the attacking fleet, which is a considerable distance away. But the bolts/spears hit the ship broadside and horizontally, while at that range they should hit at a considerable vertical angle, and along the ship fore-to-aft. The bolts could still sink the ship, just not in the fashion shown.
Using the crossbow, Bronn shoots an arrow, then quickly reloads. It is impossible to reload a medieval crossbow so quickly and easily.
Tyrion says that all the disasters in the past years were because Robert Baratheon loved someone (Lyanna Stark) who didn't love him back. This is actually true: even though Robert's Rebellion broke out because Rhaegar Targayen kidnapped Lyanna, and because Aerys executed Rickard and Brandon Stark, Lyanna's rejection of Robert was what set off this chain of events.
During the feast scene at Winterfell, a modern paper coffee cup was visible in front of Daenerys. HBO released a new version of the episode two days later with the coffee cup painted out.
During a drinking game, Tyrion correctly guesses that Brienne is still a virgin, much to her embarrassment. The scene is completely anachronistic: in a medieval-like society like Westeros, an unmarried noblewoman is absolutely supposed to be a virgin or she would bring major shame to her House.
After Jon takes the torch to light the pyre, you can see one of the dead on the pyre is breathing.