add_action('wp_head' breaks custom field ajax

I’m using custom fields on posts that feed Facebook opengraph fields in the site’s header. Since I need to insert post info that isn’t loaded until a bit later into the head section, I’ve got a function hooking into the head (add_action(‘wp_head’, ‘add_og()’,5)) and it works great, except now, when I add a custom field in the post editor, it’s no longer flashing yellow and then giving me a new field to insert another custom field. If I refresh the page, I see the custom field has been added, but the AJAX stuff that lets me keep adding them on the fly is broken. Anyone see anything like this before?