The character velocity changes while the rigidbody is kinematic

In the Walk function, the velocity changes although the rigidbody is kinematic. I am changing the rigidbody to non-kinematic after the setting the velocity.

In the Jump function, the velocity changes after setting the rigidbody to non-kinematic. I know the Jump function is the correct way to do so but how in the Walk function it's working?

Shouldn't the velocity change only when the body is non-kinematic?

  public virtual void Walk(float value) {
            var targetVelocity = new Vector2(speed * value, body.velocity.y);
            body.velocity = Vector3.SmoothDamp(body.velocity, targetVelocity, 
                      ref _velocity, m_MovementSmoothing);
            if (body.isKinematic) { body.isKinematic = false; }
         }
     
   public virtual void Jump() {
            if (body.isKinematic) { body.isKinematic = false; }
            body.AddForce(transform.up * jumpForce, ForceMode2D.Impulse);
     }