My website's posted links on facebook do not display correctly anymore

I have a facebook fan page where I post my website’s new articles.

As you can see at my fanpage’s wall, before August 23 the posted links preserved their variables, the thumbnail was showing and the title was correct (ok they’re greek but you can get the point!).

https://www.facebook.com/pages/DBPortugal/106778019351450

Yet after August 23, the posted links show just my domain without the variables (even though it links to the correct url) and there’s no thumbnail or title!

I do not remember altering my code at August 23rd, but even if I did, I cannot find what could be the cause of this problem. Facebook debugger/linter displays the correct info.