You guys are getting too worked up about that article. If you read it closely, no where in the article did it actually confirm that the Su-30 acquired or locked onto the J-20. All of it is just speculation by the author. That said, what did you guys expect the IAF spokesperson to tell the general public? That the J-20 can't be detected and the IAF has no way to engage it? Of course they are going to play up their own capabilities unless they need fundings for better weapon acquisition. Need I remind you guys that the Chinese military also claimed that they could track F-22s a while back?
Except there was every chance that the Chinese military did exactly that.
There has never been any pattern of the Chinese military misleadingly exaggerating its capabilities. If anything, the Chinese military has a consistent history of doing the exact opposite and downplaying their capabilities.
China is known to have heavily invested in anti-stealth radar tech over a multi-decade period, and have a wide array of such radars operationally deployed.
American F22s were also operating from South Korean airbases, which would have put them in range of some of these Chinese anti stealth radars.
As such, China has the means and opportunity to detect American F22s.
OTOH, India has no operational anti stealth radars that anyone is aware of. The radar on its MKIs are X-band, the very band stealth fighters are most optimised against; there has been zero suggestion that J20s ever flew close enough to the India boarder for anything India possesses to even have a chance of picking them up. And the Indian military and media both have a long and well established track record of wild exaggerations and even outright lies.
It was entirely within the realm of possibility that Chinese anti-stealth radars did their job and picked up F22s (whether they achieved good quality tracking is a very different questions); whereas Indian conventional radars being able to detect J20s that were never even in range of them is entirely outside the realm of possibility.
To equate the two is frankly an insult against the PLA and reason itself.