Model save() not save data

there is code:

    $email = $this->request->getPost('email', 'email');

    $user = users::findFirst(array(
        "email = :email: AND active = 1",
        "bind" => array('email' => $email)
    ));

    if ($user != false) {
        $newPassword = $this->generatePassword(mt_rand (8, 12));
        $hashedPassword = password_hash($newPassword, PASSWORD_DEFAULT);

        $user->password = $hashedPassword;

        var_dump($user->save());

        foreach ($user->getMessages() as $message) {
            echo $message, "\n";
        }

        exit;
    }

but the data in the column "password" are not updated!

although var_dump($user->save()); returns "bool(true)" and does not display any messages

tell me, what's wrong?