... are probably just old browser sessions with a now invalid authentication.
During migration
level=warning msg="Request failed after 29ms: Status not OK but \"400 Bad Request\" [400] fylr error: \"Duplicate file reference provided: www.easydb.example.com:eas:12345:original with file id 67890\" [EasDuplicateReference]"
... This happens if the same asset is linked in several versions in one object. In this case, the asset should not be uploaded multiple times. Instead, the same asset ID is used again in all versions. This is only logged because it is recognized as an error in a central location (API error with status code 400), but it is then evaluated by fylr restore and not treated as an actual error.