Great plugin, this is not a show-stopper:
Something is causing my site’s author archive to think that it has reached the end of the loop before it has begun – have_posts() returns false when checked after get_header() because $wp_query->current_post + 1 = $wp_query->post_count and adding rewind_posts() after the get_header call fixes the problem.
I deactivated all plugins and activating NGFB Open Graph+ was the only one to generate this error.
It is only a problem with the author archives and not with category archives.
Having said all that, it’s still possible, I guess, that the cause is more complex. Any comment?