I have not yet encountered much controversy about authorship within my department. Maybe it is in part because I’m in the humanities and many of the papers that are published are not large scale research projects that include multiple researchers from a lab.
Even when I’m researching, I don’t often come across an article that has more than one author. It happens occasionally, but probably less than 1 out of 10 times. Sometimes there are books that are authored by more than one person, but even these are often split up by chapters with individuals writing chapters for the books.
Maybe there could be conflicts with thesis advisors wanting some credit if the thesis is going to be published, but as I said I have not encountered anything like this, or even heard about it.