A paper with many egregious methodological issues is, at worst, a paper that should be ignored, as though it never happened. We cannot say that it is "wrong" or "incorrect" or "bunk" because it's a nothing, a non-argument. Until the experiments are repeated, sans egregious methodological issues, we can't logically make that determination.

So if it’s generally accepted that the world is flat, we shouldn’t listen to anyone claiming otherwise?

A better analogy would be "If it’s generally accepted that the world is flat, we shouldn't assume its round because one student was unable to measure the curvature."