Episode #1.1 - S1-E1
Corrected entry: During a conversation with Carson in the library, Lord Grantham bends down to pet the dog and addresses her as "boy" but throughout the rest of the series, Isis is a female dog.
Episode #1.5 - S1-E5
Corrected entry: While setting up a fire in lady Mary's bedroom, Daisy mentions that she "hates this room", and they show a clip of Mary carrying the dead body of Mr. Pamouk. Why would that have anything to do with Mary's room? There is no reason that Daisy would think he had been in Mary's room at all.
Correction: When Daisy was coming up the servant stairs in the hallway she sneakily saw the women carrying his body out of her room to his.
Correction: In season 1 the dog is Pharaoh, a boy. Between season 1 and 2, Pharaoh dies and lord Grantham gets Isis.