Backup Considered Successful Despite Not Uploading Anything

I was doing a test backup when I noticed this. I got Google Drive 403 errors during this test backup due to my exceeding of the daily upload quota earlier on with another backup job, but instead of failing this backup job, it still succeeded but now I cannot restore any files from it. I can still try this backup job numerous times with same results

Granted, it may be due to this backup job not being able to upload anything from the beginning compared to one that could not upload anything in the middle of the job. But won’t this lead to any confusion in the future?

This sounds related to the following issue. When all the upload attempts fail, Duplicati does not report an error:

Yes, I am indeed getting almost the same issue as described in the link you provided.

Come to think of it, I recall in one of my previous backup jobs where some of the files failed to be uploaded in the middle of the job but still continued once I managed to fix the issue (it was an UnionFS problem, just needed to create another folder in a non-full HDD). Only at the end I saw a proper error message, which was resolved once I restarted the backup job to restore those files that cannot be previously uploaded.

I wonder if this issue of false successful backup is due to Duplicati not considering none of the files being uploaded as a failed backup, and just considering if some of the files being not uploaded as a failed backup