Installed the seo plugin and after a few days created a new post type.
Now when going to the archive for that custom post type i get:
Notice: Undefined index: metakey-competition in /var/www/html/yyy/zzz/wp-content/plugins/wordpress-seo/frontend/class-frontend.php on line 482
The fix is simple:
// open class-frontend.php at line 482 and look for:
if ( !$metakey || empty($metakey) ) {
$metakey = wpseo_replace_vars($options['metakey-'.$post->post_type], (array) $post );
}
and change it with
if ( (!$metakey || empty($metakey)) && isset($options['metakey-'.$post->post_type]) ) {
$metakey = wpseo_replace_vars($options['metakey-'.$post->post_type], (array) $post );
}