Did The Chinese Violate Any Treaties?

On not making messes in space? My dim understanding is that this
remains unsettled in the Liability Convention, due to an inability to
agree on a definition of the word "debris." Any space lawyers out
there more up to date?

I'd think that, at a minimum, if any of the bits strike someone's
satellite, or ISS, that the Chinese could be held liable under the
OST. If it could be proven that it resulted from this event, that is
(probably a difficult thing to do).