Thank you for the clarification. I think I see your point now. I'll do a bit more testing with other copy tools over the weekend.
Do you agree we indeed have the same problem (I'm referring to the one you reported here)?
Note I only run into problem when I try to rclone sync --filter-from:
But if I directly rclone sync \path\to\problematic_file, it works without problem:
(I might have missed it, but) when you mentioned rclone copy t:\ --include=filename in that other post, I think it behaves the same as your test above if you add --local-no-check-updated, correct?