thats not a bug. its just logic. if you turn your head around your body still going forwards, and you throw it forwards. you just see it backwards
It's not supposed to be like that because in the other releases of the game including the latest version ( not the demo ) do work like that. So whenever you hold down the space button and use the bsoda, it works in that direction your facing even if you're holding down space but in the demo it is not like that so that's why it is called a bug and it doesn't really matter about the logic.