Sated Azir
I posted this as a bug as well, but it's been so long since the change and no one has caught it that I feel it needs to be put into Gameplay.
**The backstory: ** When Sated Devourer existed, if you were crazy and/or stupid enough to buy it on Azir and the game didn't end in 25 minutes because of your terrible jungle pick, you had the chance to get Azir with the Sated effect of applying on-hit effects twice every other attack.
Why would you ever want to do this? Wouldn't it be pointless since Azir can't apply on-hit effects with his soldiers? Well, while it is true that the soldiers' attacks can't apply on-hit effects, the reason they can't do so is because they are an on-hit effect themselves. So if you got Azir Sated, your soldiers would apply double their damage every other attack. Riot changed the animation so that they visibly attacked twice rather than having a purple body-double so as not to add lag, but kept the interaction intact.
Sated Guinsoo's, Devourer Removed: When hey removed Devourer from the game, they kept the Sated passive and put it onto Guinsoo's Rage-- you still receive the Sated buff. They even went so far as to revert the ranged nerf because of the 6-attack ramp up. However, without any mention in the patch notes, the interaction between Azir and the Sated buff no longer works. I tested it, and his normal auto attacks will correctly apply the double damage from things like BotRK, but his soldiers do not attack twice as previously intended.
So either this interaction was incorrectly removed when the items were changed, or they changed it purposefully but forgot to mention the change-- which is unlikely given that they adamantly expressed that the interaction was intended.