This often happens, the previous article didn't get any visibility so people post it again, not realizing. I think the old one is the dupe :-) We need a name for a "dupe that was ahead of its time."

I propose "dud"

I scrolled through the "new" pages quite a bit but didn't saw it. Hence I posted it. I don't know why the dupe catcher failed here.

This is intentional, since the previous submission didn't get much attention and is now too old to have a chance. Resubmissions are fine in that case and the software allows it.