I was told by Twitch staff that they had to make a simple fix. However, it has been several days with no change.
Here’s the reddit thread in question https://www.reddit.com/r/Twitch/comments/3n4q0s/embedding_html5_player_into_site/cvktiff
Yes, I’m frustrated as well. With the new player rolling out I would expect embedded players to work as expected. Currently it appears they’re using the relative domain for the javascript code needed to populate the embeded html5 player with the required channel information.
If you check the source code on twitch.tv they’re actually using iframes as well and the new player works just fine.
All we can do is wait, I suppose.