Save field with null value in translation table using ShadowTableStrategy in cakephp 5.x

I have a table with the TranslateBehavior attached to it with the ShadowTableStrategy (controllers_translations), in both tables (controllers and controllers_translations) I have a field named parent_id (I am using this similar to acl acos table), in the first record parent_id has a null value, how can I do to save this value without the validation error of existsIn in the translation table and the ones that are not null save the real value?
For some reason is saving all the records with parent_id with null value.
This is the code for translate action:

    public function translate()
        $controller = $this->Controllers->newEmptyEntity();
		if ($this->request->is('post')) {
            $controllers = $this->Controllers->newEntities($this->request->getData(''));
			$guardar = false;
			$msg = "";
			foreach($controllers as $key => $value){
					$value->_locale = 'es';
					$value->id = $this->request->getData(''.$key.'.id');
					$value->parent_id = $this->request->getData(''.$key.'.parent_id') ?: null;
					$guardar = $this->Controllers->save($value);
					if(!$guardar) break;
                $this->Flash->success(__('Los controladores han sido traducidos.'));
                return $this->redirect(['controller' => 'MyUsers', 'action' => 'login']);
			$this->Flash->error(__('Los controladores no pudieron ser traducidos. Por favor, intente nuevamente.'));
        $controllers = $this->Controllers->find('all')->contain('ParentControllers');
        $this->set(compact('controller', 'controllers'));

And this is the code for translate template:

 * @var \App\View\AppView $this
 * @var \App\Model\Entity\Controller[]|\Cake\Collection\CollectionInterface $controllers
<div class="controllers translate content">
    <h3><?= __('Traducir controladores') ?></h3>
	<?= $this->Form->create($controller) ?>
	<div class="table-responsive">
				<th><?= __('Nombre') ?></th>
				<th><?= __('Padre') ?></th>
				<th><?= __('Traducción') ?></th>
				$i = 0;
				foreach ($controllers as $value) :
				<td><?= h($value->name) ?></td>
				<td><?= $value->hasValue('parent_controller') ? h($value->parent_controller->name) : '' ?></td>
					<?= $this->Form->control(''.$i.'.name', ['label' => false]) ?>
					<?= $this->Form->hidden(''.$i.'.id', ['value' => $value->id]) ?>
					<?= $this->Form->hidden(''.$i.'.parent_id', ['value' => $value->parent_id]) ?>
	<?= $this->Form->button('Guardar') ?>
	<?= $this->Form->end()."\n" ?>

Can you please help me? I don’t know how to solve this issue and need it urgent.