When I generate a PDF for review, all the procedure content of my drop-down text appears with a number 1 (sequential numbering is lost). I am using the latest version with the newest hotfix RoboHelp 2019 classic.
IIRC, I've never had any luck getting my expanding text sections to show up properly on review PDFs (but that's still back in the RH11 days).
If it worked in earlier versions of Classic, you should report this as a bug. Please follow this link to report bugs or request features. https://tracker.adobe.com