When someone is what is traditionally understood as a loser, but only in very specific situations. Their loserdom is not consistent throughout their life. The condition oscillates from day to day. They may be a winner in some dimensions, but occasionally loser attributes often emerge when the universe throws the right (wrong) things their way.
Can you believe he didn't go home with that girl? What a situational loser. Great guy otherwise though. Madly respect and love him.