I'll start by sketching my situation. I first studied a couple of years at institution A where we were taught a couple of things concerning academic writing. (E.g. don't use passives, distance yourself from your work.) After that I did another bachelor's at another institution B (same field, same country, other city). Even though we didn't have a course dedicated to academic writing there, the promoter of my bachelor paper taught me not to distance myself from my work:
You did the research, and not some leprechauns, right? People should know that you did all this -- it didn't happen magically.
However, after my bachelor's I returned to institution A where I am currently going for my master's. The thing is: even though my grades for the first semester were good, I received feedback from different tutors and professors that my work is too personal and that I should use more passives to distance myself. This is completely the opposite advise my promoter at institution B gave me. Normally I would just go with the advise of the current institution, as that's where I am studying now and I don't want to challenge their style. The problem is that the promoter of my master thesis is the same professor as the one who promoted my bachelor paper. He changed institutions the same year that I went from institution B to A and of course he wants me to write from a personal viewpoint - whereas his (new) colleagues advised against that.
Tl;dr: promoter tells me to follow one specific (personal) style of writing, but his colleagues and other of my professor seem to like a non-personal approach better.
Note that this question isn't restricted to the distinction between personal vs. distanced/distant academic writing. I am interested more in the situation itself: what should one do when his or her promoter advises for A when the institution's approach is the contrary?
A promoter here in Belgium is a professor who is your supervisor when writing your bachelor paper or master's thesis. He or she is typically very knowledgeable about the topic you are writing in. In the process of writing your bachelor paper or master's thesis you can ask him or her questions related to your topic. Not only that, I have found that you can basically ask him or her anything related to academics - as long as it's morally and socially acceptable. He will also be the one will grade your thesis at the end of the year - possible together with a jury. The problem thus occurs that in my case this person gives me advice for something, whereas other authorities in the same institution seem to give advice against that. Since he is the one who will have to grade my work at the end of the year, I'm not sure whose advice I should follow.