Nocturn's issue

Hey, I figure out something! You know how 's w has a spell shield ability right? It don't block anything! I play 2 games of nocturne, and his spell shield didn't work on 's ult or soldier's auto (I hear it treated as spell) Second game, my spell shield didn't work on 's first Q. Also, can grab me while I have the shield on(the shield is gone and I don't receive damage). Is it only happen to me or something wrong?