Sorry.
I think it's dawning on the Chinese government a bit late that although it was a clever ploy to proliferate missile technology in the direction of Iran and North Korea to vex the United States, the vessels chosen for the mission are quite a bit less stable than Chinese foreign policy would desire. But they can't take the toys back at this point.
Their bet is that NK will prove enough of a problem to its neighbors and the U.S. that China may sit back and wait for others to invest the blood to solve this little problem. That used to look like a sound bet but these days it appears the calculation might have shaved the odds a little fine.
They'd gladly trade North Korea to the West if the result was the reclamation of Taiwan. I think that's what they're holding out for. To solve, or help solve, North Korea would be to give away a major bargaining chip. I don't think they're ready to do that yet,
Under it all, the Chinese don't like his dumb ass as a general rule of thumb.
He's gonna wake up one day 'gone' and a progressive (by N. Korean standards) China loyalist leader will be in his place.
The relationship between N. Korea and China can then be even more lips and teeth than ever.