This literally makes no sense at all. For the past year, we have been receiving pictures of J-20s in yellow primer with the WS-10X without thrust vectoring. Then all of a sudden, Minnie Chan goes on to rave about how J-20s with thrust vectoring AL-31s are going into mass production. Does this make any sense to you given the pictures we've been seeing? The designation is also completely wrong as well ... the J-20Bs should be referring to those with the WS-15s (which have the TVC ability). Here is a snippet from Pupu, who confirmed that the J-20B will have thrust vectoring on Weibo.
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As far as the WS-10X pictures go, how do you know they're J-20B? In fact, your pupu quote shows it's not the J-20B because the J-20B would have TVC. It is perfectly possible that the initial line versions with some AL-31F derivative for the J-20 are J-20 (no mod), the WS-10X J-20s are J-20As, and this purported J-20 with TVC is the J-20B.
Regarding the pupu quote, note that he's saying that the J-20B gets TVC, not that it gets the WS-15. Try thinking about the development process of the J-20.
When you think about it, the J-20 or J-20A is more or less finished. They've gotten most of the subsystems working, the FCS is increasingly mature, and the model has been IOC for 2-3 years. Chengdu has a ton of engineers with little to do now; I don't think it was anticipated that the WS-15 would be this delayed, given that the project has been worked on for more than 10 years.
Now, if the WS-15 wasn't delayed, the obvious direction would be to modify the J-20 further to enhance its capabilities. But since the WS-15 is now delayed, it is hard to add things to the J-20 and test the new J-20 because new functionality will likely include greater weight, and the J-20 is already crippled by poor T/W due to the lateness of WS-15.
So what they could try instead, then, would be to set up a J-20B with a TVC-capable Russian engine or Chinese engine. This is something that'd take a long time because you'd need to program the flight control system to support the TVC engine, as well as work out the quirks in the engine's TVC performance. Moreover, you'd want to get operational TVC models in action so they could test its reliability under real world conditions, since Russian-style 3D TVC is notoriously maintenance intensive.
They'd have to do this anyways once the WS-15 is ready, and when they're working with the WS-15, they'd have to do the work in two stages; first, to make sure the WS-15 is reliable and works without TVC, then second, to integrate the TVC with the J-20, adjust the flight control system, and ensure the TVC's reliability.
The second step doesn't require a mature WS-15 to be ready, it just requires a TVC nozzle with some other engine, Russian or Chinese.
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In either case, I don't see this as contradicting the known evidence so far. It's simply an unsubstantiated rumor from Minnie Chan, which is plausible, but lacks sufficient evidence.
For me, I don't see the point of discussing it. Minnie Chan said something that seems like good news. But it's Minnie Chan who said it, so we need others to corroborate the claim.
