lcb_cmdanalytics_scope_qualifier returns error for `${bucket_name}.${scope_name}`

The doc for lcb_cmdanalytics_scope_qualifier says "The qualifier must be in form `${bucket_name}.${scope_name}` or `default:${bucket_name}.${scope_name}`."

If I try to supply just `${bucket_name}.${scope_name}` I get an HTTP_ERROR whereas `default:${bucket_name}.${scope_name}` works correctly.

I'm not sure if this is a doc bug or implementation bug.