No, that's not about the overall correlation - it's well established that Alzheimer's is correlated with amyloid plaques. The question is whether the amyloid plaques are causing the Alzheimer's. That likely fraudulent study showed that expressing this particular form of amyloid-beta in mouse brains led to Alzheimer-like symptoms alongside accumulation of a particular fragment. That was proposed to be an early precursor to the more severe plaques seen later on (or postmortem).