Not sure if my descriptions are easy to understand. Let me give an example.
1. Link to http://eng-lish.net/
2. Click on the latest post “網站改版進行式” to open it; the Facebook comment frame shows normally on the bottom.
3. Click on the CROSS sign to close the post.
4. Click on the last page “你來我往” to open it; the Facebook comment frame DOESN’T show.
5. Close the browser, repeat step 1 and 4; the Facebook comment frame actually works fine without steps 2 & 3.