Quote Originally Posted by Sentenal View Post
Haki apparently nullified Luffy being Rubber, which is his power.
I don't know why people seem to be jumping to that conclusion. Somebody hit Luffy with Haki and he got hurt.

Why do people automatically assume that he became not-rubber all of a sudden instead of simply that he was hurt despite the fact that he was rubber?

When he was fighting Blackbeard it was obvious. He was in second gear and you could see the color and the steam fade as soon as Blackbeard grabbed him, and you could see second gear return soon after Blackbeard let him go.

Against Sentomaru, Luffy is bouncing around and Sentomaru hits him, and it hurts him. But I don't see any evidence that he became not-rubber when he was hit.