It might have just been a vision, but if it was supposed to be a scene that happened in 'real life', I would not be suprised if PJ had slipped up. Given the massive amount of material he had to deal with, I wouldn't be suprised at all if he shot Aragorn wearing it, then inserted the scene in the EE without bothering/remembering to edit it out in the coming scenes. Or than again Aragorn might not even have it after that scene, I know I can't swear either way.
