And in the parent class ?
class Parent
{
/**
* @var \Doctrine\Common\Collections\ArrayCollection
* @ODM\ReferenceMany(targetDocument="Child", mappedBy="parent", cascade={"remove"})
*/
protected $children;
// ...
}
In my project, cascade={'remove'}
works perfectly, but it's an annotation in the Parent Class, not Child class as I can see in your post.