Player acts differently if not selected in the inspector

Hi all, I hope someone could help me. I'm making a roll-a-ball game involving forces, speed and timescale. I notice a weird behaviour while playing: IF the player game object is selected in the inspector, everything works correctly as I intended in my scripts. IF NOT the player acts very differently, the applied force is weaker (so that I cannot reach the max speed), the "spin" value I created, which should decrease by 0.1 on each click, depleates with a different speed, the regeneration of the same value is faster then normal etc... Maybe it's something related to the new prefabs system of some mistake I made manipulating the timescale (and the related fixed delta time). Please help! Here's the script:

 using UnityEngine;
 using UnityEngine.SceneManagement;
 using UnityEngine.UI;
 using System.Collections;
 
 
 class PHOTON : MonoBehaviour
 {
     public Rigidbody PhotonRB;
     public float pushForce;
     public float spinMax = 1;
     public float spin = 1;
     public float spinRegRate = 0.1f;
     private Plane plane = new Plane(Vector3.up, Vector3.zero);
     public AudioSource moveSound;
     public Light photonLight;
     public bool isLightSpeed = false;
 
     private void Start()
     {
         moveSound = GetComponent<AudioSource>();
         StartCoroutine(regenerateSpin());
         spin = spinMax;
         spinRegRate = PlayerPrefs.GetInt("PlayerNewLevel");
     }
 
     public void LevelUp()
     {
         spinRegRate = PlayerPrefs.GetInt("PlayerNewLevel");
     }
 
     private void Update()
     {
         if (transform.position.y >= 5)
         {
             transform.position = new Vector3(transform.position.x, 0, transform.position.z);
         }
 
         if (Input.GetMouseButtonDown(0) && isLightSpeed == false && spin >= 0.1f)
         {
             decreaseSpin(0.1f);
 
         }
 
 
         if (Input.GetMouseButtonDown(0) && isLightSpeed == true)
         {
             RaycastHit hit;
             Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
             if (Physics.Raycast(ray, out hit, 100.0f))
                 if (hit.collider != null)
                 {
                     transform.position = new Vector3(hit.point.x, 0.5f, hit.point.z);
                     Debug.Log("hit" + hit.collider.name);
                 }
         }
         else
         {
             return;
         }
     }
     void decreaseSpin(float amount)
     {
         spin -= amount;
 
         if (spin <= 0)
         {
             spin = 0;
         }
     }
 
     IEnumerator regenerateSpin()
     {
         while (true)
         {
             if (spin < 1)
             {
                 spin += spinRegRate * 0.001f;
                 yield return new WaitForSeconds(0.01f);
             }
             else
             {
                 yield return null;
             }
         }
     }
 
     IEnumerator lightSpeed()
     {
         isLightSpeed = true;
         Time.timeScale = 0.05f;
         PhotonRB.isKinematic = true;
 
 
         yield return new WaitForSeconds(0.5f);
      
 
         isLightSpeed = false;
         Time.timeScale = 1f;
         PhotonRB.isKinematic = false;
         //LightSpeedSlider.gameObject.SetActive(false);
     }
 
 
     private void FixedUpdate()
     {
         photonLight.intensity = Mathf.Lerp(1f, 30f, PhotonRB.velocity.magnitude/100);
        // photonLight.range = (PhotonRB.velocity.magnitude);
         PhotonRB.mass = Mathf.Lerp(1f, 0.01f, PhotonRB.velocity.magnitude / 100);
         PhotonRB.drag = Mathf.Lerp(0f, 1f, PhotonRB.velocity.magnitude / 1000);
 
         if (PhotonRB.velocity.magnitude >= 100f)
         {
             StartCoroutine(lightSpeed());
         }
 
         if (Input.GetMouseButtonDown(0) && isLightSpeed == false)
         {
             moveSound.Play();
             var ray = Camera.main.ScreenPointToRay(Input.mousePosition);
             float enter;
 
             if (plane.Raycast(ray, out enter))
             {
                 var hitPoint = ray.GetPoint(enter);
                 var mouseDir = hitPoint - gameObject.transform.position;
                 mouseDir = mouseDir.normalized;
                 PhotonRB.AddForce(mouseDir * pushForce);
             }
         }
     }
 }