I recently upgraded a project from RoboHelp 2019 Classic to RoboHelp 2020 (v2020.1.54). I have a topic called Appendix B that displays when I output to HTML, but does not appear when I output to Word/PDF. I duplicated the Online TOC and switch the duplicate TOC to a Book TOC format so that I could add a "front matter" Table of Contents in the Word/PDF. Appendix B is in the new Book TOC, hide in output is not selected, and for some reason when I output a document, Appendix B does not appear there. It skips right from Appendix A to Appendix C.
Any ideas why this might be happening? The only way Appendix B is different is that it has several lengthy tables on it, but that shouldn't make the page disappear entirely.
Are you using conditional tags? Perhaps the Appendix B topic has a condition applied that is excluded from the PDF output?