@Override
  ReplyProcessor21 createReplyProcessor() {
    return abortBackupFactory.createReplyProcessor(this, getDistributionManager(), recipients);
  }
AbortBackupStep overrides addToResults in order to include members with empty persistentIds
(such as the sender).
geode-core/src/main/java/org/apache/geode/internal/cache/backup/AbortBackupStep.java