Whenever a research is done, you must reject or accept a null hypothesis (the one you consider is not correct) or your work hypothesis (the theory you think is must probably accurate or close to the truth) usually, when performing a research, you will not always obtain positive or statistically significant results, that validate your hypothesis. Is actually, not unusual that extremes (or extraordinary results) come out (unexpected for several reasons: incorrect size of the sample, improper selection of the subjects- a bias- lack of correct determination of the variable measured or failure to determine the type of the variable-numerical, categorical, ratio,etc-)
Positive or negative results are yet, results whether they prove or reject your hypothesis. Failing to establish a scientific hypothesis does not necessarily mean that they did something wrong, it just says that the hypothesis tested does not approach correctly to the epistemological truth (ultimately, any research is only a mere approximation to reality). Therefore, when two scientists deny sharing<em> unusual results</em>, they are acting unethically, hiding results that can mean something from a different point of view.
reference
Nicholson, R. S. (1989). On being a scientist. Science, 246(4928), 305-306.