Note to Macbeth, Act 1, Scene 3, lines 72-73: "The Thane of Cawdor lives, / A prosperous gentleman"

Act 1, Scene 3, line 72.
Shakespeare appears to have forgotten that in the previous scene, Ross described Macbeth's successful battle against "Norway himself ... / Assisted by that most disloyal traitor / The thane of Cawdor." If the thane of Cawdor is a traitorous prisoner, he's not a "prosperous gentleman."