Facebook Comments conflict on url of a product

I'm using Facebook Comment from "http://www.opencart.com/index.php?rout ... 0comments" for my page http://sieuthithietbivanphong.com

With the product url "http://sieuthithietbivanphong.com/may-p ... -1435.html", the Moderation appear, but no comments (actually 4)
With the product url "http://sieuthithietbivanphong.com/may-p ... -1435.html". the Moderation disappear, but comments appear.

I do test on "https://developers.facebook.com/docs/plugins/comments".
Anyone please help me.