Index: src/wp-admin/includes/class-wp-press-this.php
===================================================================
--- src/wp-admin/includes/class-wp-press-this.php	(revision 31611)
+++ src/wp-admin/includes/class-wp-press-this.php	(working copy)
@@ -640,7 +640,7 @@
 						$key = $this->_limit_string( wp_unslash( $key ) );
 
 						// Sanity check. $key is usually things like 'title', 'description', 'keywords', etc.
-						if ( empty( $key ) || strlen( $key ) > 100 ) {
+						if ( ( empty( $key ) && 0 != $key ) || strlen( $key ) > 100 ) {
 							continue;
 						}