Following the directions Peter posted to his RoboHelp site (https://www.grainge.org/pages/snippets/snippets.htm#:~:text=Adobe,problems%20in%20Firefox), I created a sample project with a topic that had multiple numbered lists using the "counter-reset" parameter. I confirmed that the output showed correctly in Chrome and Edge:
First List
Step 1.
Step 2.
Second List
Step 1.
Step 2.
And that the lists displayed incorrectly in Firefox:
First List
Step 1.
Step 2.
Second List
Step 1.
Step 3.
Using Source view, I searched for "counter-reset" and replaced it with "counter-set". I generated the project and then viewed the output in Chrome, Edge, and Firefox.
The lists displayed correctly for all browsers.