I mean this makes some sense, The PRC is nothing if not cautious, and they seem to have taken note of the mistakes of the USSR. The US loves to brag that the sr-71 their top of the line spy plane was made with Soviet tungsten that they got by having a complicated list of shell companies and essentially confusing the Soviets. Given that it doesn't suprise me in the slightest that the PRC doesn't grant export to the US