Not a bug, Protect has a higher priority than aqua jet for sure (even if it has pranster) but Pranster and Aqua jet have the same Priority so it comes down to speed at that point. The Azu was faster than your Mega-Ban so the disable went 2nd. I recreated the battle on showdown for a visual if thats more your thing. (mind the struggle at the end, that is what would happen if choice items worked with bosses if you disable them)
With The battle log it shows the the pokemon is still asleep, its up to to the player to point that out and see. If you dont see thats a mistake on your part that the opponent can use to gain an advantage.