Unable to get the latest value even cache is flushed

I am using Laravel 10 and Redis as cache driver.

Precisely, I am able to clear cache but I still get the old cached value. I have a Eloquent model called SystemSetting. I created a helper class to fetch data from the model. Then, I have a global helper function gss() which will be used in blade file to get specify system setting value.

if (!function_exists('gss')) {
    function gss($key, $fallback = null)
    {
        return wncms()->system_setting()->get($key, $fallback);
    }
}

wncms()->system_setting() will instantiate the system setting helper class and call the get() function.

//in SystemSettingHelper.php class
    function get(string $key, $fallback = null)
    {
        $systemSettings = $this->getList();
        return $systemSettings[$key] ?? $fallback;
    }

in the get() function of class SystemSettingHelper, it call getList() to get an array of SystemSetting value and return value by array key

    function getList(string|array|null $keys = [])
    {
        $method = "getList";
        $shouldAuth = false;
        $cacheKey = wn('cache')->createKey($this->cacheKeyPrefix, $method, $shouldAuth, wn()->getAllArgs(__METHOD__, func_get_args()));
        $cacheTags = ['system_settings'];
        $cacheTime = 3600;
   
        // wn('cache')->clear($cacheKey, $cacheTags);
        //cache()->tags($cacheTags)->flush();
        return cache()->tags($cacheTags)->remember($cacheKey, $cacheTime, function () use($keys){
            try{
                if(!wncms_is_installed()) return [];
                $q = SystemSetting::query();
 
                if(!empty($keys)){
                    if(is_string($keys)){
                        $keys = explode(",", $keys);
                    }
                    $q->whereIn('key', $keys);
                }
    
                //return all keys if empty $keys is passed
                return $q->pluck('value', 'key')->toArray();;
            }catch(\Exception $e){
                info($e->getMessage());
                return [];
            }
          
        });
    }

In above getList() function, $cacheKey is just a string generate from parameters passed. Its always the same when its called from get(). Then I use a cache tag ['system_settings'] to tag these cache.

Whenever I update some of the system settings. I will call cache()->tags(['system_settings'])->flush();. So matter what the $cacheKey it was, getList() should have the fresh new value because all cache key should be tagged by ['system_settings']

After I updated value of system setting with key version, I should get the latest value by calling gss('version'). However, I will get the old version value.

The following is some investigation I have done:

1. flush cache and compare values. gss() show the old one while Eloquent method show the latest one.

        dd(
            cache()->tags(['system_settings'])->flush(), //return true
            gss('version'), // return '3.0.6'
            SystemSetting::where('key','version')->first()?->value, // return 3.0.7
        );

1. tags() function of Redis cache is intact. I write a simple test for it. When I flush tagged cache, $x always return a different value. When I disable the cache. It show the cached value.

 $x = time();
 $cacheTag = ['test'];
//cache()->tags($cacheTag)->flush();
$cache = cache()->tags($cacheTag)->remember('mytest', 3600, function() use($x){
      return $x;
});

dd($cache);

1. I have multiple laravel website on the same server so at the beginning I suspect it read cached data from other applications. Then I check the cache prefix of the app. In configcache.php and cache prefix is generated from APP_NAME (env don't have CACHE_PREFIX) which I am sure its specific to this application. Besides the old value retrieved from gss('version') is also specifc to this application.

    'prefix' => env('CACHE_PREFIX', Str::slug(env('APP_NAME', 'laravel'), '_').'_cache'),

To sum up. My problem is that even if I cleared cache with the tag ['system_settings']. gss() still get the old cached value. I have no idea where to debug. Please help.