It is stated in the work Akabir ka Taqwa:
“Shaykh al Hadith stated: I have heard the practice of my teacher’s shuyukh was that if a student brought up a point of disagreement during a lesson whose answer was inexplicable to him, he would go up to the teacher for an explanation and deliberate with him.
Maulana Thanawi (Allah sanctify his secret) used to say that I have established the system of tarjih al rajih (i.e. giving preference to the preferred) so that if someone notices a mistake in my works then he may inform me, and if I am convinced of my mistake I will publicly proclaim it. Therefore, I have, in the past, wholeheartedly affirmed places where I have committed errors or lapses. When I am not convinced of my mistake, I reproduce the opinion of the one differing and so one may follow whichever position appeals to his heart. This is what I have always done, never imposing my own opinion on anyone.
This is due to the blessing of Maulana Muhammad Ya`qoub (Allah have mercy on him), for although this blessed disposition was in all the akabir it was not quite like that of Maulana Muhammad. If something was mentioned that did not give him full conviction, he would jet-off during his class to get a book and would, without hesitation, state, ‘I have not understood this. Please, if you may discuss it with me.’ Then, after the discussion he would return and recapitulate to the other students what the teacher said, stating ‘Maulana explained this part in this way…’
Further, if on a specific point a student discusses something with the teacher and turns out to be correct, the teacher would immediately during the class go back on his position, stating in clear words that he had made a mistake…”
(Pg 56-57, Maktaba al Shaykh ed.)