Why does the normal vector come out like this when I shoot a ray while walking backwards?

I'm going to implement a gun.

I want to implement the Particle system, so I need the normal vector of the hit place.

If I shoot a ray while walking forward, it works properly, but if I shoot a ray while walking backwards, the hit.normal bounces in a strange direction and can't be implemented properly.

What's the reason for this?

 RaycastHit hit = new RaycastHit();
 Ray r = new Ray(Camera.main.transform.position , Camera.main.transform.forward );
 Vector3 hitPosition = r.origin + r.direction * 200.0f;
 
 if (Physics.Raycast(r, out hit))
 {
             Debug.DrawLine(r.origin, r.origin + r.direction * 200.0f, Color.green);
             Debug.DrawLine(hit.point, hit.normal, Color.red);
 }

forward

backward

This situation is when the camera looks forward and steps back.