Yes a lot of people forget that the relations between China and Russia have always been shacky at best, they both have the common goal of being the main hegemonic power of Eurasia so of course they aren't best buddies, the only reason they aren't enemies is because they have the common enemy of the US however that tense relation has been slowly degrading over the years due to the fact that Russia is still recovering after the fall of the USSR while China is a rising power, and then you have the usual Chinese bullshit of stealing your shit and then say they made it, IIRC, a few years ago Russia made a deal with China, it would give China a few hundred fighter planes with the condition that China wasn't allowed to build them, China turned around, build exact replicas of those planes, changed their colour scheme and model name and whoala, a new 100% original plane, this didn't make the Russkies happy and now with China claiming Vladivostok is only making the relation worsen.