Your link isn't working for me. I'll test out some other browsers shortly. I'm surprised that Google wouldn't optimise the HTML5 player to fit YouTube considering they own both products.
I think they think they have optimized it. Chrome uses much less bandwidth for a partial play than the other browsers.
You're right, it must be a Chrome issue. I just clicked your link and it worked this time the video is having the same jittery playback I experience on YouTube's HTML5 player.