Two penny from my side on what is happening in LAC. With its current posture China is only trying to flare up Indian side and make them commit to some short of Political outburst. It is recently been shown by GoI that currently they are not taking anything for granted and opened up like never before its Western Front. During all this, something interesting happened on other part of world. On 23rd and 24th June twenty-seventh plenary meeting of NSG had taken place. I'll be quoting a few lines from public statement over here.
Now it seems something had brewed up in this plenary meeting which did affected China. China does have veto right in NSG like its other member. But it simply can't go on vetoing against India on one point year after year. Internal politics plays a major role over here. Along with the fact that India had made some serious steps towards getting permanent membership of UNSC, there are reasons enough for China to be pissed off.
So in this condition, the best China could do is to flare up the border dispute with India and try to make the Indian politburo utter some serious miscalculated threat in media and in turn give Chinese the much needed ammo to counter Indian progress both in NSG as well as UNSC. Please note that its their spokesperson and media which is making noise. No statement had been issued on behalf of PLA till now. Moreover who would come up with such childish logic of keeping forward a treaty signed in 1890 when neither Bhutan was sovereign state nor was China. On top of that Xi has to show something to rising demand of democratic government in Hong Kong.
BTW, link to the public statement of NSG Plenary meeting is attached herewith.
http://www.nuclearsuppliersgroup.org/images/NSGPlenaryBernPublic_Statement_final.pdf