Eloquent chunk() missing half the results

I have a problem with Laravel's ORM Eloquent chunk() method. It misses some results. Here is a test query :

$destinataires = Destinataire::where('statut', '<', 3)
    ->where('tokenized_at', '<', $date_active)
    ->chunk($this->chunk, function ($destinataires) {
        foreach($destinataires as $destinataire) {
            $this->i++;
        }
    }
echo $this->i;

It gives 124838 results.

But :

$num_dest = Destinataire::where('statut', '<', 3)
    ->where('tokenized_at', '<', $date_active)
    ->count();
echo $num_dest;

gives 249676, so just TWICE as the first code example.

My script is supposed to edit all matching records in the database. If I launch it multiple times, it just hands out half the remaining records, each time.

Any suggestions ?

via Chebli Mohamed