It shouldn’t be really big unless its associated dblock is really big because Remote volume size got raised. Default is 50 MB, which limits the dblock size size, which limits dindex. Do you have a big dblock file there?
After decrypt, you can look in the .zip file to see what dblock name is in the vol folder, then check file’s size.
Probably, and looking up the message, this looks like a Wasabi (which you use?) error message some see. Wasabi support might be able to comment on whether it’s of long-term concern. They might ask what you used for download, and I don’t know what you used for your download-and-decrypt. Guessing not Duplicati, although Duplicati.CommandLine.BackendTool.exe could have done a download of the specific desired file.
It’s pretty technical. You could probably edit the database Remotevolume VerificationCount to 0 to persuade the semi-random file chooser to choose that one again. I take it you don’t want to also validate all other files.
You might be able to validate all other files except for the dblock files, if this new variation works for Test too:
--full-remote-verification (Enumeration): Activates in-depth verification of
files
After a backup is completed, some (dblock, dindex, dlist) files from the
remote backend are selected for verification. Use this option to turn on
full verification, which will decrypt the files and examine the insides
of each volume, instead of simply verifying the external hash, If the
option --no-backend-verification is set, no remote files are verified.
This option is automatically set when then verification is performed
directly. ListAndIndexes is like True but only dlist and index volumes
are handled.
* values: True, False, ListAndIndexes
* default value: False