the ball does not have to leave the hand to make it a pass.
As long as the QB's arm starts moving forward with the ball in his hand, it becomes a pass.
I've seen that slo-mo'd and adjudicated time after time in various games, and that's always the standard.
NOW, IF the ball is knocked loose BEFORE the arm starts forward, then it doesn't matter if the empty arm goes forward. That's a fumble.
But Mahomes clearly had begun the throwing motion before the ball was struck.
Ramily!
