This ties up with other information I have heard.
On behalf of Dr. Jianguang Shen:
“Following the change in the renminbi’s managed peg system on 11 August, China has reportedly sold over USD100b in US treasury to defend the currency against further depreciation. In our view, capital outflows could continue, as the government is adamant on maintaining a stable exchange rate, while eroding foreign reserves and facing potential risk from external debt exposure. In our view, this could mean challenging times ahead for the PBoC until selling pressure is reduced through economic improvement in 4Q and delays in the US rate hike.”