Aren’t the Russians still mad over the Chinese ripping off the Su-30 for their carrier?
For that reason they want the Chinese to pay billions dollars before delivery for the entire batch of dozens planes, charging them $80 millions or so per copy.
It is right enough cash to fund finishing T-50 5 gen R&D and to subsidize a fleet of newer jets for Russian and Indian AFs, outclassing these Chinese Su-35s.
They’re mad but money talks and the Chicoms have plenty of it. It seems Russia is resigned to the fact that China will copy and hawk its hardware. The sticking point over the past few years was the Russians wanted the Chinese to buy fare more than the 20 or so they wanted.