A Wrinkle In Time

I'm no expert on the mechanics of time but if boy genius over here designed a device to go back 4 seconds in time, why is it I don't go back 4 seconds in time?

(Also, that ult hit anyway. However if there wasn't a malfunction the ult woulda hit in both scenarios.)

To clarify just in case: -Ult hitbox is off -Rewinding back 4 seconds doesn't actually rewind 4 seconds, the clone should freeze in place if you are going to that specific point when you rewind.