Playerprefs stop saving after a while

Hi folks. I'm having a trouble with playerprefs on my WebGL game.It's working properly at the beginning but after few minutes, saving function is start delaying. Game normally autosave itself every 3 minutes. But if I plays the game one hour and reopen the game, my loaded data is about 10 minutes older. Also I'm seeing this warning error is flowing on my console; Warning: 8 FS.syncfs operations in flight at once, probably just doing extra work. This warning number continues as long as the game is open. Maybe somethings wrong on my code. Please have a look.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerPref : MonoBehaviour {
 
     public Karakter karakter;
     GameObject lvlup;
 
     public Levelup levelup;
     GameObject expver;
 
     public WaveManager waveManager;
     GameObject expSetup;
 
     public Crafting crafting;
     GameObject craft;
 
     public Aspects aspect;
     GameObject asp;
 
     //public Achievements achievements;
     //GameObject achie;
 
     public SkillTree skilltree;
     GameObject skills;
 
     public Forge forge;
     GameObject soulcraft;
 
     public Torch torch;
     GameObject lightIt;
 
     public float savetimer;
 
     void Start ()
     {
         lvlup = GameObject.FindGameObjectWithTag("karakter");
         karakter = lvlup.GetComponent<Karakter>();
         expver = GameObject.FindGameObjectWithTag("expbar");
         levelup = expver.GetComponent<Levelup>();
         expSetup = GameObject.FindGameObjectWithTag("gamemaster");
         waveManager = expSetup.GetComponent<WaveManager>();
         craft = GameObject.FindGameObjectWithTag("crafting");
         crafting = craft.GetComponent<Crafting>();
         asp = GameObject.FindGameObjectWithTag("aspect");
         aspect = asp.GetComponent<Aspects>();
         //achie = GameObject.FindGameObjectWithTag("achievement");
         //achievements = achie.GetComponent<Achievements>();
         skills = GameObject.FindGameObjectWithTag("skilltree");
         skilltree = skills.GetComponent<SkillTree>();
         soulcraft = GameObject.FindGameObjectWithTag("forge");
         forge = soulcraft.GetComponent<Forge>();
         lightIt = GameObject.FindGameObjectWithTag("torch");
         torch = lightIt.GetComponent<Torch>();
 
         savetimer = 0;
         levelup.saveTime = true;
         //PlayerPrefs.DeleteAll();
 
         if (PlayerPrefs.GetInt("Saved") >=1)
         {
             //Karakter
             karakter.karakterStartHp = PlayerPrefs.GetFloat("karakterStartHp");
             //karakter.karakterHp = PlayerPrefs.GetFloat("karakterHp");
             //karakter.karakterMaxHp = PlayerPrefs.GetFloat("karakterMaxHp");
             karakter.healthMultiply = PlayerPrefs.GetFloat("healthMultiply");
             karakter.damage = PlayerPrefs.GetFloat("damage");
             karakter.damageMultiply = PlayerPrefs.GetFloat("damageMultiply");
             karakter.EnemyAliveBonus = PlayerPrefs.GetFloat("EnemyAliveBonus");
             //karakter.totalDamage = PlayerPrefs.GetFloat("totalDamage");
             karakter.range = PlayerPrefs.GetFloat("range");
             karakter.fireRate = PlayerPrefs.GetFloat("fireRate");
             karakter.critChance = PlayerPrefs.GetFloat("critChance");
             //karakter.critDamage = PlayerPrefs.GetFloat("critDamage");
             karakter.critMultiply = PlayerPrefs.GetFloat("critMultiply");
             karakter.lifeSteal = PlayerPrefs.GetFloat("lifeSteal");
             karakter.penetration = PlayerPrefs.GetFloat("penetration");
             karakter.damageReduction = PlayerPrefs.GetFloat("damageReduction");
             karakter.poisonChance = PlayerPrefs.GetFloat("poisonChance");
             karakter.poisonDamageMultiply = PlayerPrefs.GetFloat("poisonDamageMultiply");
             karakter.lastStandDamageMultiply = PlayerPrefs.GetFloat("lastStandDamageMultiply");
   
         }
     }
     
     
     void Update ()
     {
         PlayerPrefs.SetInt("Saved", 1);
 
         savetimer += Time.deltaTime;
         if (savetimer >= 200)
         {
             levelup.saveTime = true;
 
             savetimer = 0;
         }
 
         if (levelup.saveTime == true)
         {
             SaveGame();
             Debug.Log("Saved");
             levelup.saveTime = false;
         }
         
     }
 
     void SaveGame()
     {
         //Karakter
         PlayerPrefs.SetFloat("karakterStartHp", karakter.karakterStartHp);
         //PlayerPrefs.SetFloat("karakterHp", karakter.karakterHp);
         //PlayerPrefs.SetFloat("karakterMaxHp", karakter.karakterMaxHp);
         PlayerPrefs.SetFloat("healthMultiply", karakter.healthMultiply);
         PlayerPrefs.SetFloat("damage", karakter.damage);
         PlayerPrefs.SetFloat("damageMultiply", karakter.damageMultiply);
         PlayerPrefs.SetFloat("EnemyAliveBonus", karakter.EnemyAliveBonus);
         //PlayerPrefs.SetFloat("totalDamage", karakter.totalDamage);
         PlayerPrefs.SetFloat("range", karakter.range);
         PlayerPrefs.SetFloat("fireRate", karakter.fireRate);
         PlayerPrefs.SetFloat("critChance", karakter.critChance);
         //PlayerPrefs.SetFloat("critDamage", karakter.critDamage);
         PlayerPrefs.SetFloat("critMultiply", karakter.critMultiply);
         PlayerPrefs.SetFloat("lifeSteal", karakter.lifeSteal);
         PlayerPrefs.SetFloat("penetration", karakter.penetration);
         PlayerPrefs.SetFloat("damageReduction", karakter.damageReduction);
         PlayerPrefs.SetFloat("poisonChance", karakter.poisonChance);
         PlayerPrefs.SetFloat("poisonDamageMultiply", karakter.poisonDamageMultiply);
         PlayerPrefs.SetFloat("lastStandDamageMultiply", karakter.lastStandDamageMultiply);
     }
 }