Sometimes the likes count, sometimes they are zeroed…

The referenced page has at least four Open Graph protocol code blocks defining information including the canonical URL to use for the page.

Pass your URLs through the Facebook Debugger to see parsing issues preventing Facebook from properly indexing your page and populating full data from a Like Button action.

Hello Niall,

thanks for the info, but in the meantime I fixed the problem by installing a WP plugin which removes the #more tag. So when clicking the “read more” link the URL of the full post is also the permalink without any appendix.

A simple addition to functions.php does the trick.

See this Digging into WordPress article: Cool Things You can do with the WordPress “more” Tag. Skip down to the part “Stop more link from jumping to middle of page”