The move Uproar seems to be working in a funny way...
Instead of acting like petal dance, forcing your pokemon to keep performing Uproar for 3 turns, (While petal dance lasts from 2 to 3, even if it seems to be a bugged move aswell, being able to last 4!) the skill perform a double hit on the enemy, without any further aciton, letting your pokemon able to permorm a different move next turn.
tltr: It works like double slap!!