Thunderlord's Decree works weird with items

So I was trying to learn some combo's on Riven in practice mode.I tried to do E, Hydra active, W Q double cast then i noticed that Thunderlord's didn't proc. So i turned on no cooldowns and spammed Hydra active Thunderlord's wouldn't proc. So I thought maybe items don't work with Thunderlord's, so I bought Blade Of The Ruined King and spammed that and thunderlord's did proc so I tried with alot of items. All of the Hextech items worked, then I bought hextech revolver this caused Thunderlord's to proc after only 2 basic attacks while Lich Bane and Sheen didn't do. But i don't get why hextech revolver can proc Thunderlord's in 2 basic attacks and Hydra active doesn't proc Thunderlord's at all even after 2 auto attacks and then Hydra active.

Can someone explain this?