It should be the Primary Contact. If you go to Edit Issue and change the Primary Contact. I can't remember the particulars, but the Requested By is sometimes the Primary Contact. I think Requested By is populated when someone reassigns the request to another Team, it puts that person in the Requested By and leaves the Primary Contact. But when there is no Requested By the Primary Contact is used. Not sure if that makes sense – it's fuzzy in my head . But if you're trying to accomplish what I think you are, Primary Contact will work for you.