Board Thread:Theories and Speculation/@comment-30241447-20170409050955/@comment-25122992-20170409102222

Well, Tailed Beasts cannot be sealed into anyone, as we know, hence the term "compatibility" (though we don't know exactly what does it mean). Also, we already met one case where even amongst relatives not all of them were "compatible" with the beast (I'm reffering to Gaara's sitiation where only he could become Shukaku's Jinchuriki amonst his siblings). So Boruto can be very well incompatible with Kurama, that would explain Momoshiki's words quite enough.