Just commented about it below but here is a link to one of the articles discussing it.

The only reason I would believe China would make a move is really two-fold. One they are nearing a population cliff and this was what Russia was facing when they first launched the Ukrainian Invasion. Also, war is a known historic and fantastic way to continue to quiet the discontent in the Mainland and reboot its economy since it has been sluggish esp. by their standards compared to the last 20-30 years.