At first is was like, ok he reflected a sandman.
big fuck**g deal. But then I realized that it stunned you and you reflected it and I was like L01 wat?
But are you sure you reflected it? Maybe it just bounced off you with enough force to send it that far back.
First thing I noticed is that the team color aura particle effect around the ball is actually in front of it in when looking at it in slow mo. Now if the hitbox is attached to the ball but the aura registers the stun this would make sense.
It looks like you blasted the ball and not the aura. There is on frame at 0:11 where the aura is going away from you and the ball is going towards you.
Or the more realistic explanation is that one your client you blasted it while at the same time on the scout's client he hit you, so you got stunned but the ball kept on going back.
When I look at it one frame at a time it looks like it hit you.
This still amazes me though.