Source Reference:

• Component: bbPress:: bbp-topic

  File: /bbp-includes/bbp-topic-functions.php :: Trac Source Line: 1483

  				// Update the reply
  				wp_update_post( $postarr );
  
  				// Adjust reply meta values
  				bbp_update_reply_topic_id( $reply->ID, $destination_topic->ID                           );
  				bbp_update_reply_forum_id( $reply->ID, bbp_get_topic_forum_id( $destination_topic->ID ) );
  
  				// Do additional actions per split reply
  				do_action( 'bbp_split_topic_reply', $reply->ID, $destination_topic->ID );
  			}
  		}
  
  		// It is a new topic and we need to set some default metas to make
  		// the topic display in bbp_has_topics() list
  		if ( 'reply' == $split_option ) {
  			$last_reply_id = ( empty( $reply ) || empty( $reply->ID        ) ) ? 0  : $reply->ID;
  			$freshness     = ( empty( $reply ) || empty( $reply->post_date ) ) ? '' : $reply->post_date;
  
  			bbp_update_topic_last_reply_id   ( $destination_topic->ID, $last_reply_id );