I created Sections in the project TOC and generated Responsive HTML5 online help.
Let's pin this down to your project or a browser issue.
Generate the About RoboHelp sample project. Does that work correctly? If it does, then we need to look at your project.
Create a new TOC in it and use the AutoCreate icon on the toolbar. Output to a new folder using that TOC. It may not be the way you want users to see the topics but that doesn't matter for this purpose.
Does that work?
Where do I find the About Robohelp sample project?
Should be in your My Documents\My Robohelp Projects iirc
Did you resolve this?
Yes. I reviewed the About Robohelp sample project and found out what I was doing wrong. Adobe Online help for Robohelp leaves a lot to desire!