The github download does not have this line in that file which was causing the issue
/* Adjust the authorship 'default for post type' text string based on the post type */
$field_defs['authorship']['options']['-'] = sprintf( $field_defs['authorship']['options']['-'], ( ( isset( $options[ 'noauthorship-' . $post_type ] ) && $options[ 'noauthorship-' . $post_type ] === true ) ? __( 'don\'t show', 'wordpress-seo' ) : __( 'show', 'wordpress-seo' ) ) );
so commenting out the line 451 by adding two forward slashes in your plugins folder in that file also solves the issue
wp-content/plugins/wordpress-seo/inc/class-wpseo-meta.php
//$field_defs['authorship']['options']['-'] = sprintf( $field_defs['authorship']['options']['-'], ( ( isset( $options[ 'noauthorship-' . $post_type ] ) && $options[ 'noauthorship-' . $post_type ] === true ) ? __( 'don\'t show', 'wordpress-seo' ) : __( 'show', 'wordpress-seo' ) ) );