Oh, I'm sorry. I meant "SPACE UP" and "SPACE DOWN" ... I'm referring to events the operating system sends when you press keys. Applications, like 7d2d see those events and react. Using a program like AutoHotkey, you could send "SPACE DOWN, SPACE UP, SPACE DOWN" really quickly. That would play out much faster then the actual jump takes place.
I was guessing you're not using software to trigger a sequence like that and speculating maybe your keyboard could somehow do that if you partially pressed the Spacebar. Then, if that happened, maybe the game would do something weird, like a hop.