Board Thread:Speculation House/@comment-190.47.114.141-20170910035917/@comment-26397825-20171011140337

Jaune has had issues from day one actually using his aura, even after it was unlocked. See the fight against Cardin, where he got bruises.

Pyrrha asked him why he didn't 'activate' his aura in the Emerald Forest to protect himself from the tree branch. From her words I think it's safe to presume that you can deactivate your aura after it's been unlocked. By this same logic, you should also learn to keep it active subconciously, something that Jaune may not have managed to do properly yet. He's only been training for a year and had never heard of aura before that, plus he skipped the combat schools and didn't have private tutors to teach him all this stuff. He missed out on a lot of basic stuff, which may include the lesson on how to subconciously keep your aura active during a fight.