premise: The Louvin Brothers were an American musical duo composed of brothers Ira Lonnie Loudermilk (1924–1965) and Charlie Elzer Loudermilk (1927–2011), better known as Ira and Charlie Louvin. The brothers are cousins to John D. Loudermilk, a Nashville Songwriters Hall of Fame member.
hypothesis: Ira and Charlie Louvin are cousins.
reason:  Ira and Charlie Louvin are brothers, not cousins. It may have been difficult for the system because it mentions them being cousins to someone else.