Let prove that it happens, I keep my right to doubt on it with my evidence.
At the time, there're only Su-30MK2V in 370 division, and it's not Thang Long
In 2011, there're only 12 Su30MK2V for 370 division, in Southern assigned to 935 Regiment
In June 2012, 371 ( Thang Long ) division receive first 3 of Su30MK2V assign to 923 Regiment ( in Middle land of Vietnam ). That means in June 2011, even June 2012, there aren't 4 plane of Su30 in Thang Long.
It could happen if China J10A was invited to 371 division in Southern of Vietnam for exercise in 2011. Or maybe exercise between J10A vs Su30 within China territory.
And an air exercise between Vietnam and China is unlikely. If any please provide the details
To me, there's little chance for J10 vs Su-30MK2V engaged in the same exercise in 2010-2011 ( maybe between PLAAF ). And the real life never proved the point of antonius, while Vietnam continue to order more and more Su-30. They didn't do so if they found Su-30 can't even beat J10A
What's conversation? Do you mean create a thread here, and everything on it come true?
Below rumor ( from antonius link ) was posted 5 July 2011
Vietnam SU-30 locked by J-10, 10 times
Vietnam SU - 30 by J - 10 Lock 10 times
News from: China's large military forum insider "pupu", this person is very well-informed and reliable news, has revealed a large number of messages.
According to him: Vietnam June 13 exercises, j-10 in the South Vietnamese Air Force over the lock, "Thang Long" division of a SU-30 four-plane formation in Viet Nam can not find the J-10's case, J -10 with the fire control radar to lock them a dozen times, each frame is locked s-30 at least twice. At the same time, also cut more aircraft formation with the ground command center of the radio communications, and forcibly inserted into the communication channel, and more pilots on the good-neighborly friendly relations with the Chinese started a warm and amicable discussion.
See the location of Su-30 : 923 Regiment and 935 Regiment.
923 Regiment base atleast over 400 kilometers from China - Vietnam border.