Help! wp book plugin messed up my featured image showing for facebook shares.

I’m really confused about what was changed or added by the wp book plugin. Yesterday I finally figured out how to get facebook to show the image I set as featured image when a link is shared from my blog. I added the following code to my templates functions.php

function insert_image_src_rel_in_head() {
global $post;
if ( !is_singular()) //if it is not a post or a page
return;
if(!has_post_thumbnail( $post->ID )) { //the post does not have featured image, use a default image
$default_image="https://wickedgoodsavings.com/wp-content/uploads/2015/04/header2.jpg"; //replace this with a default image on your server or an image in your media library
echo '<meta property="og:image" content="' . $default_image . '"/>';
}
else{
$thumbnail_src = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'medium' );
echo '<meta property="og:image" content="' . esc_attr( $thumbnail_src[0] ) . '"/>';
}
echo "
";
}
add_action( 'wp_head', 'insert_image_src_rel_in_head', 5 );

It was working great until i installed wp book and made a facebook app for my site per wp book plugin instructions. I got about halfway through the setup for the plugin before a noticed there was this issue with the facebook images.

I uninstalled the plugin and deleted the facebook app, but it did not resolve the issue. Using the facebook debugger tool, It’s saying “fb:app_id hasn’t been included in the meta tags. Specify the app ID so that stories shared to Facebook will be properly attributed to the app. Alternatively, app_id can be set in url when open the share dialog. Otherwise, the default app id( 966242223397117 ) will be assigned.”

It pulls the featured image as og:image, but then shows the default image when it is shared.

What can i do to fix this?

Urls I’m having this problem with:
this post
and this one