Riven is not procing the new keystone
As I now know that Rivens 3rd Q and W are hard CC i can confirm that neither of them proc the new keystone that gives a shield for hard CC. I've played her in a few games with that keystone (The first game was where i thought that it wasn't a bug and that i was an idiot for thinking it was, and the second game was because i forgot to change it back to TL). You can recreate by going into a game as riven and using your abilities on a champion.