hi,
really, not an issue with --backup-dir,
as --backup-dir does work with rclone copy and with rclone sync
when a source file is deleted, the behavior of rclone copy and rclone sync are different.
with rclone copy, the dest file is not deleted.
" Doesn't delete files from the destination"
with rclone sync, the dest file is deleted.
"Destination is updated to match source, including deleting files"
however, when using rclone sync --backup-dir, the dest file is moved from f:/test to f:/archive
that is the behavior you seem to want.
this is easy to test. with your command, just change rclone copy to rclone sync --dry-run