Maybe the result is down to some issue with the regiment that equipped J11Bs (although that seems unlikely since they are getting the new birds first because they have a track record of being a strong and capable regiment, so the pilots should be of a high enough quality and be experienced enough to not disgrace themselves even if they were just flying J11As), or it could just be a case of the pilots not yet being fully familiar with their new birds at the time of the exercise. I think the latter is more likely, as I already said, the pilots equipped with J11Bs would have been quite capable in their own right before the re-equipping as they would never have gotten the new jets first if they were getting their butts kicked in all the exercises beforehand.
When you consider the improvements in the avionics of the J11B compared to the J11A, it would not be hard to see how someone who learnt to fight in the J11A might struggle a little with all the new equipment, concepts and workload of the new plane.
In a fight, the person who knows his bird implicitly and do not even have to think about the mechanics of performing actions and only need to decide what he wants to do will have a massive advantage over someone who needs to both actively concentrate to remember how to make his plane do certain things as well as having to decide what he wants his plane to do.
I am inclined to give the J11B and their pilots the benefit of the doubt for now, but will obviously revise my position if the J11B performs badly in subsequence exercises consistently as well. But hopefully it won't come to that, and this drubbing might just give the J11B pilots the kick up the butt they need to really focus their minds onto the task of fully mastering their new birds so that they can show everyone what the J11Bs can do next time.