Hi there,
With Event Espresso Pro, it appears that the conflict will only manifest itself if both the Publicize and Sharing modules are active. When either of these modules are active, opengraph tags get added to the head of the document, which seems to be causing the trouble.
These modules can be deactivated on the main Jetpack settings page by clicking the Learn more button, then clicking the Deactivate button that appears to the right of the Learn more button.
If you'd prefer to use either of these modules, you can disable the opengraph tags by adding a function like this to a custom functionality plugin -or- if you have Event Espresso's custom files add-on installed, you can add it to the custom_functions.php file:
function disable_jetpack_og_on_regpage() {
if ( is_page(4) ) {
remove_action( 'wp_head', 'jetpack_og_tags' );
}
}
add_action( 'template_redirect', 'disable_jetpack_og_on_regpage' );
In the above code example, the main registration page as set in Event Espresso>General Settings has the ID of 4. You'll need to swap out the page ID value with the one that's set on your site.
I've submitted a ticket to the Event Espresso developers so they aware of the issue.