[plessl]

I can confirm, that the suggested fix still works: You can add your backup volume to the Spotlight privacy pane immediately after formatting the disk with Diskutil (i.e. before SuperDuper is ran for the first time for this volume).

I don't know whether adding the backup volume later, i.e. after some backups have been made with SuperDuper, works now. But since there is such an easy workaround I don't consider this an important problem. You can easily reformat the volume later, add the volume to Spotlight privacy and make a backup after that.