Issues sharing blog articles onto Facebook

Over the past few days I've noticed the articles I share from my blog onto Facebook have not been shared properly, by this I mean I am the only one who can see the shared posts on the page. My other page admin cannot see the posts & neither can those who have liked the page. The posts have a "boost unavailable" icon beneath where it normally would say "boost post" . The older posts from a few days back & prior are still available to boost though. The recently posted links also say "Posted by comments" Rather than "posted by (admin name)" . Any known reason behind this issue?

The problem is resolved when the URL is directly pasted onto the page, but using the sharing widget directly from the blog causes this. Could this be an issue with the widget?