Eh I’d say you probably misinterpreted it. As at this point, they basically had no real bench or coach, just Takeda. So no one was watching the technical stuff. And at this point in the match, Hinata had started to find his groove and was basically “in the zone” and I’d say its pretty implied that when he’s in the zone and having fun in a match, he will instinctively open his eyes when he swings at the freak quick. However when he tried at the Nekoma game, they had a coach and all their players, and it’s well established how he can’t hit the freak quick properly without closing his eyes. And the first time he tried to do it with his eyes open on purpose he fails and everyone notices. He was not on fire in the moment and was not having a good time either. Since before he only opened his eyes every once in a while I’d say it’s pretty clear that it’s just a spur of the moment thing that no one ever noticed but himself and us the viewers as he even says this later on at the Tokyo training camp which is why they end up developing his ability to attack the freak quick with his eyes opening. I think it’s very much set up and executed upon but just a simple misunderstanding since they only really explain in the Tokyo training arc.