Result is not appearing when filtering the cache data: Laravel 5.1

What is it about ?

Filtering the cache data using two approaches. Below is the code.

Attempt : 1

$Categories = \Cache::rememberForever('Categories', function() {
    return \App\Models\Skill\Category_Model::all();
});
$Category = $Categories->where('CategoryID', $request->input('CategoryID'));     

Attempt : 2

$Categories = \Cache::rememberForever('Categories', function() {
    return \App\Models\Skill\Category_Model::all();
});
foreach($Categories as $Category) {
    if($Category->CategoryID == $request->input('CategoryID')) {
        $Category->Category = $request->input('Category');
        $Category->IsActive =  $request->input('IsActive') == "on" ? 1 : 0;
        $Category->save();
        \Cache::forget('Categories');
        return Redirect('Categories-List');
    }
}

Question:

While using Approach : 1, results are always null, where as while using Approach : 2, there is no Problem. Is there anything wrong ?

via Chebli Mohamed