Two-armed Shanks after he saves Luffy As a One Piece fan who doesn't read the manga I must ask this:

In this flashback when Ace meets Shanks, Ace says: 


  "My brother was always talking about you as his lifesaver"


As you are aware, Shanks lost his arm when he saved Luffy. However, at 0:43 you can clearly see both of his arms.

Does this happen in the manga or is it just an animation mistake?
The meeting between Ace and Shanks does happen in the manga, but according to the One Piece Wiki on Episode 461 where this happens, Shanks having two arms appears to be an error in the animation. 

Personally, I do agree that it was an animation fail, since it was long after Shanks saved Luffy.