Probably when you move ahead of the target as you are riding it, a server tick ordeal. So when you're infront of it, you knock them back with the shotgun's on-hit effect, thus ending it.
Regardless, I think Wild Ride should grant a temporary knockback immunity to both you and your ridee(?), in so to future proof this.
Regardless, I think Wild Ride should grant a temporary knockback immunity to both you and your ridee(?), in so to future proof this.