Laravel 5.5 Array Diff with bug?

I'm developing in Laravel 5.5 and Php 7.1.9 and I came across the following problem:

I have the following Checkboxes screen and when checking any of the fields, arraydiff of Laravel insists on returning the wrong difference value, ie if I check any of the checkboxes of the image it returns 1 => 2 as difference see the image.

Screen Print  

ReturnusingLaravel'sArrayDiffunction

CodesnippetgeneratesCheckBox

{{--percorrendoatabelaparaexibiroschecks--}}@foreach($usersas$keys=>$dados_users){{--seorestodadivisãoforparseráexibidonacolunaA--}}@if(!($keys%2))<trclass="">    
                <td></td>             
                <td></td>   
                <td></td>      
                <td></td> 
                <td></td>                                                           
                <td class="">                                   

                    <p><input type="checkbox" class='chk' name="user_id[]"  id="user_id" value="{{ $dados_users->id }}"> {{ $dados_users->name }}</p>             
                    <p><input type="hidden" class='chk' name="user_id_desmarcados[]" id="user_id_desmarcados" checked value="{{ $dados_users->id }} "></p>              
                </td>                                                           
        {{-- se não será exibido na coluna B --}}                                                                                             
        @else                                                
                <td></td>        
                <td class="">                                                                                                                                                                      
                    <p><input type="checkbox" class='chk' name="user_id[]"  id="user_id" value="{{ $dados_users->id }}"> {{  $dados_users->name  }}</p>  
                    <p><input type="hidden" class='chk' name="user_id_desmarcados[]" id="user_id_desmarcados" checked value="{{  $dados_users->id }} "></p>                         
                </td>                                                        

            </tr> 
        @endif                                                           

{{-- finalizando o foreach --}}
@endforeach 

Controller code with ArrayDiff (Laravel)

public function store(PerfisuserRequests $request)
    {
        // recebendo todos os dados do formulário    
        $dataForm = $request->all();   


        // repassando o valor do Id 
        $id_perfis = $dataForm['perfis_id'];

        /*************************** Verificando os dados que foram Marcados na Inclusão ****************/
        /***********************************************************************************************/

        // repassando os dados para a variavel collection para verificar com Array Diff
        $collection = collect($dataForm['user_id_desmarcados']);

        // repassando os dados para a variavel collection para verificar com Array Diff
        $collection2 = collect($dataForm['user_id']);    

        // realizando a verificação atráves do Array Diff
        $diff = $collection->diffKeys($collection2);

        // aqui será retornado a diferenca entre os Arrays
        $diferenca = $diff->all();

        dd($diferenca);

For Comparison Effect (after all it was not working the way I wanted it), I decided to use the direct function of php to call array_diff and to my surprise, the return was favorable, that is, I got the return I needed to see the examples.

Print return with Check 1 checked

ScreenPrintwithCheck2Checked

Array_Diff code snippet

 $teste = array_diff($dataForm['user_id_desmarcados'], $dataForm['user_id']);

    dd($teste);

So I ask:

Would this be a Bug in the Laravel 5.5 diff array or am I doing something wrong?

Is there any problem in not using the native function of array diff in laravel?