CakePHP 3 - how to patchEntities where form data is collected within a foreach - cakephp-3.0

Question

My scenario is similar to this post here: CakePHP 3 - Form data format for patchEntities()
However, I am trying to update multiple entries that are represented within a foreach.
The Form looks like this:
<?= $this->Form->create(null, ['url' => ['controller' => 'Products', 'action' => 'index']]); ?>
<?php foreach ($products as $key => $product): ?>
<?= $this->Form->hidden("{$key}.id", ['value' => $product->id]); ?>
<?= $this->Form->control("{$key}.reduced_price", ['value' => $product->reduced_price]); ?>
<?= $this->Form->control("{$key}.price", ['value' => $product->price]); ?>
<?php endforeach; ?>
<?= $this->Form->end(); ?>
Output of $this->getRequest()->getData()
0 => array:3 [▼
"id" => "7319"
"reduced_price" => "987"
"price" => "200"
]
1 => array:3 [▼
"id" => "7318"
"reduced_price" => "875785"
"price" => "299.5"
]
Controller Action:
if ($this->getRequest()->is('post')) {
$products = $this->Products->find()->toArray();
$entities = $this->Products->patchEntities($products, $this->getRequest()->getData());
$this->Products->saveMany($entities);
}
If I follow ndm's advice then the entries would have to be updated, but they won't. But why?
Update:
If i use save() inside a foreach the records are being saved
$products = $this->Products->find()->toList();
$entities = $this->Products->patchEntities($products, $this->request->getData());
foreach ($entities as $entity) {
$this->Products->save($entity);
}
But why does saveMany not work for me?