You doubt about cycle or loop for

I have a question about ciclo for , is that I have a form where I send and I receive the following variables:

case 'updatePD': //ACTUALIZACION DEL COLABORADOR
if(!empty($_POST['consecutivo'])){

$n=count($_POST['consecutivo']);
$iddatospersonales=$_SESSION['iddatospersonales'];
$cedula=$_SESSION['numdocumcolaboradorview'];

for ($i=0; $i<$n; $i++) {
    $rutaarchivo="../../assets/files/upload/archivo/";

    if (empty($_POST['idprocesodisciplinario'][$i])) {
        $_POST['idprocesodisciplinario'][$i]=0;
    }

    if (empty($_POST['causa'][$i])) {
        $_POST['causa'][$i]=-1;
    }

    echo "CAUSA:  ". $_POST['causa'][$i]."  CONSECUTIVO:  ".$_POST['consecutivo'][$i];
    echo "<br>";

    $query=$obj->post_ejecutar("SELECT * FROM procesodisciplinario WHERE 
idprocesodisciplinario=".$_POST['idprocesodisciplinario'][$i]." 
ORDER BY idprocesodisciplinario");
    $opcion=pg_fetch_row($query);

    if(!empty($_FILES['cargadisciplinarios'])){
        if(!empty($_FILES['cargadisciplinarios'])){
            $cargadisciplinarios=$obj->cargar_archivo($_FILES['cargadisciplinarios']['name'][$i],$_FILES['cargadisciplinarios']['type'][$i],$_FILES['cargadisciplinarios']['size'][$i],$_FILES['cargadisciplinarios']['tmp_name'][$i],$_FILES['cargadisciplinarios'],$rutaarchivo,$iddatospersonales,'DISCIPLINARIO',$cedula);

            try {
                $filedisciplinario=$cargadisciplinarios['filename'];
            } catch (Exception $e) {
                echo "NO ES UN ARCHIVO VÁLIDO";
                $filedisciplinario="";
            }
        }
    }

I have a select that depending on the user's choice is enabled or disabled the other select (The Cause):

The problem or the error I have is that when doing the following validation:

if (empty($_POST['causa'][$i])) {
    $_POST['causa'][$i]=-1;
 }

If that variable does not arrive as a result, you should bring me -1 in the cause, but that is not the problem, but in the order that it is brought to me, it is not the correct one because it arrives last. , when in reality I should get this image first annex to make it easier to understand: