Doctrine: A new entity was found through the relationship with selected elements - symfony

Question

In a symfony command script, i find entities like this :
$this->em->getRepository('AppBundle:House')->findBy(...);
Foreach element, i call a service method with my element as an argument.
In my Service, i have an error when i try to create an element linked to the "house"object
this doesn't works :
$glass = $this->em->getRepository('AppBundle:Glass')->findOneBy(['house' => $house->getId(), 'name' => $name]);
if (! $glass instanceof Glass) {
$newGlass= new Glass($house, $name);
$this->em->persist($newGlass);
$this->em->flush();
}
this works but i don't want to have to find again my existing house i already founded in my command script :
$existingHouse = $this->em->getRepository('House')->find($house->getId());
$glass = $this->em->getRepository('AppBundle:Glass')->findOneBy(['house' => $house->getId(), 'name' => $name]);
if (! $glass instanceof Glass) {
$newGlass= new Glass($existingHouse, $name);
$this->em->persist($newGlass);
$this->em->flush();
}
Can you help me to understang what's wrong ?
Glass constructor
public function __construct(House $house, string $name)
{
$this->name= $name;
$house->addGlass($this);
$this->house= $house;
}
house orm file :
oneToMany:
glasses:
targetEntity: Glass
mappedBy: house
cascade: ["persist"]
glass orm file :
manyToOne:
house:
targetEntity: House
cascade: { }
fetch: LAZY
mappedBy: null
inversedBy: glasses
joinColumns:
house_id:
referencedColumnName: id
orphanRemoval: false