Nonsense. We produce various version of WS-10 engine to equip locally used J-10A/B so there is little reason to divert attention to JF-17 engine when we have our hand full on more important project.
In addition, you have to understand that this sale is mainly to seek cooperation and influence in Latin America and it is NOT about money. We made record profit base on normal economic trade alone, so this deal is pocket change for us. What this deal does, however, is giving us more influence while not offsetting the balance of power between Brazil/Argentina (we have good relation with them since they are part of BRICS). It is also carefully graft in a way that we sell JF-17 instead of J-10s to avoid misunderstanding with UK which have the whole EU backing. We have good relation with EU so no reason to upset over dispute which is irrelevant to us. You are right, nothing to worry about. If we want to give you headache, we would done so easily.