I actually found a resolution to this issue yesterday. My problem occurred with output generated from RH11 on Windows. I haven't tested all outputs or all versions, but I can confirm the problem occurs with Multiscreen HTML5 in RH11 and RH2019 Classic, and just search for Responsive HTML5 for RH2019 Classic.
All features worked fine when viewing the help in Internet Explorer, but not when viewing in Chrome. I don't have Firefox or a Mac+Safari to test, but the principle would be the same for those browsers.
I found it occurred in the following circumstances:
1. Opening the output from a local file system (e.g. c:\myproject_output\index.htm) in Chrome, and
2. Blocking third party cookies.
If I enabled third party cookies, testing locally worked fine. I'm not sure why, but perhaps the cookie is set inside an iframe and Chrome defines an iframe as a third party? I haven't looked at the output in RH2019 New to see if this theory works there, though.
However I didn't want to enable third party cookies. Poking around in the browser developer console indicated that cookies, localStorage and sessionStorage is blocked on the local file system.
I finally found I could add file:///* to the allowed sites list and then the help would run locally even with third party cookies blocked.
To set this in Chrome:
1. Open Settings.
2. Search for and open Site Settings.
3. Open Cookies and site data.
4. In the Allow section, click Add and enter file:///*. Make sure you enter 3 forward slashes and an asterisk or it won't work.