Combination not showing in backoffice in product page prestashop 1.7

add code

Thanks for sharing your issue here.
I suggest you to replace below code in /src/PrestaShopBundle/Controller/Admin/ProductController.php file to get shop id instead of 1
$attributeGroups = $this
->getDoctrine()
->getManager()
->getRepository('PrestaShopBundle:Attribute')
->findByLangAndShop(1,1);

Replace with below code :
$attributeGroups = $this
->getDoctrine()
->getManager()
->getRepository('PrestaShopBundle:Attribute')
->findByLangAndShop(1,(int)['shop_id']);

If you are using multi-language then you can also try as below :
$attributeGroups = $this
->getDoctrine()
->getManager()
->getRepository('PrestaShopBundle:Attribute')
->findByLangAndShop((int)$languages[0]['id_lang'],(int)['shop_id']);