Contributors API reports incorrect number of contributors

When querying the contributors API (projects/:id/repository/contributors) an incorrect number of contributors are returned for large projects (e.g https://gitlab.com/api/v4/projects/4339844/repository/contributors?per_page=100 reports 58 rather than the 70+ or so)

I suspect this might be a similar issue to #234116 (closed) in that the commit limit means older contributors are ignored.