You are making a good point, Azure DevOps is implying here that the person who worked on a branch is also the initiator of the PR. This is not something that is 100% guaranteed, because it can happen that I created a dev branch, worked on code, made several commits, then my teammate creates a PR from my branch.
(The “most recent pusher” setting is probably closer to what you are looking for, which controls based on who pushed the latest commit from a local repository.)
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