okito

I have same problem with you. I have no idea what to do, except modify that file.
change :

if ( is_array( $cached_list ) && !empty( $cached_list ) ) {

to :

if ( isset( $cached_list ) && is_array( $cached_list ) && !empty( $cached_list ) ) {

and
change :

if ( is_array( $expired_list ) && !empty( $expired_list ) ) {

to :

if ( isset( $expired_list ) && is_array( $expired_list ) && !empty( $expired_list ) ) {

Try this :

global $wpseo_og;
remove_action( 'wpseo_opengraph', array( $wpseo_og, 'description' ) );

ps. It is work for og_title but I never try to remove description.

You must edit wpseo-functions.php.
Change this :
utf8_encode( substr( strip_shortcodes( strip_tags( utf8_decode( $r->post_content ) ) ), 0, 155 ) ),
to :
wp_html_excerpt( strip_shortcodes( $r->post_content ), 155 ),