TIL you can parry the Night’s Cavalry and it immediately knocks them off their horse

I’ve tried to parry these guys a few times in different playthroughs but I never had success. I did have a real challenge getting parries against them after the discovery, it seems like it’s not just a timing thing but also a spacing thing. Parrying tree sentinels is a lot easier even though you don’t get a riposte against them, just a stagger. I’m guessing you can only parry the glaive Night Riders and not the flail variety.