Pasting link to WP page in FB facebook broken

Most of our pages are created from our database. When I paste the URL into a Facebook wall post, for example, the data fetched is not the entire relevant page, but the generic page title, description, and thumbnail, from our site (index).

Here’s an example URL: https://la.shambhala.org/program-details/?id=91910

Anything obvious?
Anything to try?

Oh, and we don’t have “write” access to the server at this time. #$%^&