Looks like this user may be one associated with the imported Yahoo Groups archive material, or probably from more recent imported myBB material (the forum has migrated platforms a couple of times. The myBB user accounts were explicitly imported with some associated user profile info, though the Yahoo Groups users were not, so have only a nominal username in profile)
Created at date is 2011-11-28 - though I see an updated date much more recent - 15 July 2020, without user actually ever visiting this site/forum incarnation? Maybe some automatic process did the updating?
When I manually searched for that user profile, I saw that the user is showing as approved (probably approved automatically during the import process from MyBB - though if so, why is it showing as unapproved in query? Either way, if this is some systematic issue with the user profile imports, there should be hundreds of others the same showing up as unapproved but active, not just one)