Internationalisation happens when third country becomes a party to the issue. Barring China, literally everyone called it bilateral. (And dont say calling it bilateral is a win because India said its an internal issue, they said that just to have more to give if any talks take place. Thats how Diplomatic level talks are done, always start with strings tighter than what u are comfortable with and slowly loosen them so other party thinks it got u to do it and yet you are still in ur comfort zone.)
Chinese ambassador's statement can't be taken as the statement of other member's statement as nobody authorised them.
It was being discussed already, the media was all over it for years....media is still over it and will remain so...what changed? Pak was talking about Kashmir in every forum, it still is doing the same thing.