I had to reinstall RoboHelp 2019 on a Windows 10 machine. Since then, when I generate responsive HTML output, I lose the indent settings for all lists and other styles with an indent. For example, my left indent is set to 36pt but the output does not add the indent yet in the project it displays as it should and the indent settings for the style are correct.This was not happening before I had to change operating systems and reinstall RoboHelp. I am using RoboHelp 2019 Classic edition. It is not a browser issue as the same thing occurs on Chrome, IE, and Firefox.
Did you apply all the updates after re-installing?
The only other thing I could suggest is checking to make sure the output is using the CSS you think it should be using. Maybe it's not.