I am author in two author papers, but also in 200 author papers. Nothing wrong with it. In our field they are studies among a dozen centers, where each center has to do something and the results are pooled to some central hub. If I do a relatively easy data prep before sending to the hub, I go among the authors, it is just the way it works. A huge work that is spreaded thinly, or else can't be done unless you ask people to work without attributio. That might work once or twice, but not more, if you are the person who ask for favours but returns nothing.