Why is Terrain Sample height resetting player rotation

When I rotate the player on input with MoveRotation no issues however when I try to sample the terrain height to adjust the transform then the player character only moves forward on the terrain since the rotation gets reset to ZERO.` void Rotating(float horizontal, float vertical, float slerpDampTime) { Quaternion camRotation = mainCam.transform.rotation; camRotation.x = 0; camRotation.z = 0; // we need some axis derived from camera but aligned with floor plane Vector3 forward = mainCam.transform.TransformDirection(Vector3.forward);//forward of camera to forward of world //local forward vector of camera will become world vector position that is passed to the forward vector of the player (target) rigidbody //(The cam and player(target) vector will now always point in the same direction) forward.y = 0f; forward = forward.normalized; Vector3 right = new Vector3(forward.z, 0.0f, -forward.x); Vector3 targetDirection = (horizontal * right + vertical * forward); if (targetDirection.sqrMagnitude > 1f) { targetDirection = targetDirection.normalized; } Quaternion targetRotation = Quaternion.LookRotation(targetDirection, Vector3.up); Quaternion newRotation = Quaternion.Lerp(GetComponent().rotation, targetRotation, slerpDampTime * Time.deltaTime); GetComponent().MoveRotation(newRotation); } void LateUpdate() { if (Terrain.activeTerrain != null) { var newpos = transform.position; newpos.y = Terrain.activeTerrain.SampleHeight(transform.position); transform.position = newpos; } } }