I think if it had an element of truth, it would be found from more reliable primary sources.So Russians finally gave up their only edge
"Russia is helping China develop submarine, aeronautic and missile technologies" FT
"Type 096 SSBN is being developed with support from Russian technology for making its propulsion system more silent, according to US naval researchers" Hopefully 095/096 will be on par with project 545 or even better
Probably some level of Russian engagement are in Chinese design and vice versa. Both governments realize cooperation with allies can unlock new design perspectives. But in practice it is not so easy to conduct joint research. If you look at how Russia and China's newest SSNs projects, they all diverge very far from eachother. There is no indication that the 2 countries will ever pursue a joint SSN design.
Russia has also not made some incredible leap in quieting technology that US/China should jump at the chance to discover what they learned. At least nothing public would indicate that the Russians advanced like that.