Well yes, and they say why in the article. It doesn't yet have the degree of freedom in its hips to balance properly. That's not especially hard though - a pi

Well yes, and they say why in the article. It doesn't yet have the degree of freedom in its hips to balance properly. That's not especially hard though - a pivot around the main spring axis would do the trick, and the dynamics of that part are well-understood at this point.