Facebook share is good, simple, lets us share almost everything on web in seconds. But Facebook caches already shared urls/pages for better performance. This causes issues at time when we update the title or picture being shared or the description of the page because facebook still shows the older version of the page.
This post is focused on how to test exactly what your page will look like, even the minor details.
The site with more than 500 Million Users, is tough to get away with bugs. They obviously cannot regenerate each and every flow after integration of their new features.