Changes to Facebook Custom Link Previews
"On July 17 Facebook will deprecate the ability to customize link previews for Facebook group and profile posts, in an effort to reduce misrepresentation of link content," according to this article on Hootsuite's blog. "These changes will apply to all of Facebook’s API integration partners."
This will affect Facebook profile and group posts. Page updates will come later. Any scheduled posts will publish without any link customizations after July 17.
Read the article for more details.
Thanks to @MakalaArce for pointing us to this story. "I anticipate greatly missing this ability.." she writes. "This increases the importance of websites optimizing their content to be 'social share friendly' from the get-go."