FLOW3 Association and JsonView

class Hotel{
/**
* Users is an array collection of User objects
* @var \Doctrine\Common\Collections\Collection<\DKM\Services\Domain\Model\User>
* @ORM\ManyToMany(inversedBy="hotels" , cascade={"persist"})
* @ORM\JoinTable(name="dkm_services_domain_model_hotel_user_join")
*/
protected $users;

/**
* Get the Hotel's users
*
* @return \Doctrine\Common\Collections\Collection The Hotel's users
*/
public function getUsers() {
 return $this->users;
}
/**
 * Sets this Hotel's users
 *
 * @param \Doctrine\Common\Collections\Collection $users The Hotel's users
 * @return void
 */
public function setUsers(\Doctrine\Common\Collections\Collection $users) {
    $this->users = $users;
}

}

class User{

/**
     * @var \Doctrine\Common\Collections\Collection<\DKM\Services\Domain\Model\Hotel>
     * @ORM\ManyToMany(mappedBy="users" , cascade={"persist"})
     */
    protected $hotels;

/**
     * Get the Users's hotels
     *
     * @return \Doctrine\Common\Collections\Collection The Users's hotels
     */
    public function getHotels() {
        return $this->hotels;
    }

    /**
     * Sets this User's hotel
     *
     * @param \Doctrine\Common\Collections\Collection $users The User's hotels
     * @return void
     */
    public function setHotels(\Doctrine\Common\Collections\Collection $hotels) {
        $this->hotels = $hotels;
    }


}

I have an association table (jointable) with users and hotels (this is automatically generated by a doctrine:update command) and with two columns:

user|hotel
a      b
c      b

So, two different users should belong to the same hotel. But if I dump the hotel object with the users associated, the users seem to be assigned to two different hotels.

And If I render the hotels thru a JsonView, I cannot display any user (actually, there's no "users" data in it) in the Json string.

Thank you in advance for any hint!
Davide