Reference and screen shots at

https://tex.stackexchange.com/questions/695624/adding-hyperref-package-makes-tex4ht-change-its-split-level-order

I noticed big problem. When I was using split level on document, which should split it at section level because I used level 2, it did not.

It turned out when I remove the hyperref, then it does the right thing and split at section level.

See How to split an article at the subsubsection level using tex4ht? for splitting levels.

Here is a MWE

-------------------------
\documentclass[12pt]{article}
\usepackage{hyperref}

\begin{document}
\section{section one}
text

\section{section two}
text
\end{document}
---------------------

Compiled using

make4ht -ulm default -a debug foo.tex "mathjax,htm,2"

gives this HTML

enter image description here

You see, it did not split the page. Now by just removing the \usepackage{hyperref} and compiling again, it now gives this correct page, where it puts each section on its own page

enter image description here

I checked this in TL 2023 and also in TL 2022.

No wonder I always had hard time with split levels with tex4ht. It works different depending if \usepackage{hyperref} is used or not. To get it to split at section level when hyperref is loaded, level 3 should be used and not 2. But this is all wrong. Splitting level should not be affected by loading hyperref

Thanks
--Nasser