The problem is indeed caused by the plugin “Contextual Related Post”. In your function twcm_get_description() the used function get_the_excerpt() (line 134) returns the content of the box with related posts.
To avoid this, I changed the source of twitter-cards-meta/twitter-cards-meta.php as follows (line 134 and 135):
if($desc=="")
{
$desc=trim(get_the_excerpt());
}
to
if($desc=="")
{
//$desc=trim(get_the_excerpt());
$desc = trim($post->post_content);
}
It is a quick workaround and I’m not shure, if it is the best idea, but it works for now.
