Alright, I have set up a new test server on the latest GitHub version. I took a sample page and compared to yours.
My finding is that your site has a weird OG going on, which I do not know whether is customized by your end? Because the one supplied by our stock version has a different output and is working fine. The problem is that your og Type is indicating a website, while the actual stock one will say it is an article, and your url is root url while the one supplied by stock will have the non-SEF url formatted url values.
Please see attachment of both HTML source comparison for this.
Please view source, (or use Facebook Debugger) on this - https://next.php-fusion.co.uk/news/1/test-news-subject