I ran into this issue as well, it looks like some tabloid press processes still rely on having all the pages as separate PDF files, with specific numbering schemes as well.
I tried the Designer workaround, but it's looking like it's stuck on something... and I'd rather not have some third-party app to do the job.
But in context, this is the only issue I've had so far while trying to create a new workflow from scratch, after years of not doing any layout work at all. And compared to any remaining sane memories on how Adobe software worked, Publisher has been remarkably trouble-free, managing to do pretty much everything I could imagine it needing to do.
Heh, naturally there's been some crashes (my computer is old), but even then the software happily restored everything where things were. Even the filesize got smaller. 🙂
Thanks, all the people involved.