Does it finish successfully? If so, the exhaustive final search phase for missing blocks did its job. Sometimes it looks everywhere and comes up empty anyway. This results in a broken backup…
Have you always been using Beta versions? That would rule out Canary damage to the backup.
Damage from Beta versions before 18.104.22.168 is also a possibility unless initial backup was 22.214.171.124.
What exactly does this mean? The original install never gets updated. A folder of updates does.
Duplicati’s start begins on original install (e.g. Program Files\Duplicati 2 on Windows) then finds whatever the newest update is and runs it. The restart by the UI Activate button doesn’t work on Windows service, however a service restart or system reboot should pick up the update version.
Uninstall and reinstall from the .msi file will also take care of things by updating in Program Files.