What OS are you running and and what destination are you using?
Are you using a --usn-policy setting other than the default value of off?
--usn-policy
This setting controls the usage of NTFS USN numbers, which allows Duplicati to obtain a list of files and folders much faster. If this is set to “off”, Duplicati will not attempt to use USN. Setting this to “auto” makes Duplicati attempt to use USN, and fail silently if that was not allowed or supported. A setting of “on” will also make Duplicati attempt to use USN, but will produce a warning message in the log if it fails. Setting it to “required” will make Duplicati abort the backup if the USN usage fails. This feature is only supported on Windows and requires administrative privileges.
Default value: “off”
(By the way, I edited your post by adding “~~~” before and after the messages / logs to make them easier to read.)