Today we released an important update that changes the behavior of the contributor filter. Before, if you had a contributor selected, the metrics would be calculated over all of the pull requests they were involved in. No matter if they were a reviewer, merger or author. Now when you filter on contributors, it will only include pull requests (and calculate their metrics) from which they are an author.
The motivation behind this change is that we wanted to allow teams to be fully in control over improving their metrics, now by only including pull requests which the team authors, this makes that possible.
Pro-tip: this change is particularly useful when you want to exclude pull requests authored by bots.