think it was @TheAncientCenturion who sent a marineford page in which Doffy talks to Ivankov saying he "doesn't know how Iva and Kuma are related", despite the fact that last chapter we learned that both of them were two of the main pillars from the Revo Army. Also, during Sabaody, apparently it wasn't a wide known fact that Kuma was a Revo anyway, as he had to whisper it to Rayleigh, as if it was some sort of secret.