I don’t know what to say about that. I just tested to a b2:// URL from Windows and Linux, and mine worked, however it said *** Remote folder is not empty, aborting when I tried to reuse a bucket and folder, and could not create a new bucket but could create a new folder (I just changed the name from an old URL). Got a few upload failures both cases (regular Duplicati would probably just have retried those up to 5 times).
That’s what I would have suggested (maybe after retrying a plain recreate again). You need that database.
Thinking about an earlier statement I made, I think that test of SharpAESCrypt with do and WinRAR was an appropriate proof of a corrupt file, because you decrypted (as much as could be done) before trying unzip. You might want to at least run one --log-file log to see if you get any Warnings about bad lengths, like I did. Running with a higher –backup-test-samples than the rather low default of 1 for awhile might also be good.
One thing I forgot to ask is whether anybody was on a recent Duplicati version. There was an update of the AWSSDK DLL in 2.0.3.24 (I think), and I’m hoping it still works fine with all of the S3-compatible providers…