Aura amp has always been active since Pyrrha awakened Jaune’s Aura, it’s what allowed Jaune, beside natural talent, to be hitting as hard as he does, tank hits as good as he does, because Aura amp has been amplifying his abilitys to compete with people with years of training in aura, combat, and intense physical conditioning. With the added bonus of increasing his mental abilities allowing him to learn and grow faster.
TDLR: Aura Amp is a broken semblances, basically free kiao-ken.
Also; Good fucking thing Jaune didn’t get trained earlier in life or he’d be unfucking stoppable, doesn’t matter if you’ve trained the same amount of time, he would learn faster, hit harder, takes hit’s better, and grow faster than you, also doesn’t matter if you break his aura, he’ll restore it near instantly and heal back all the damage you’ve done. He’d be the next best thing to a god.