Based on what I am reading in that tread, it seems like MW misrepresented his conversation with EB.
^ I remember MW wrote in a different thread that he talked to EB and that she was supportive of his study (or something like that), I'm too lazy to dig the thread.https://www.econjobrumors.com/topic/are-all-previous-mutual-fund-flow-pressure-papers-wrong/page/2
Try reading the papers. EB's paper documents that the the fund flow pressure measure, which is supposed to be orthogonal to fundamentals, is correlated with a bunch of observable characteristics, which raises serious doubts about using the measure to isolate non-fundamental variation in pricing but leaves open the possibility of something like propensity score matching to fix the problem. MW's paper shows that the measure is literally an inadvertent transformation of contemporaneous returns, which means that the measure as generally constructed is unsalvageable. Both papers make important contributions, but there is a reason MW's paper is R&R at JF and EB's paper is R&R at JFE.