I just noticed that some older posts are broken after LaTeX2HTML updates. I’m disabling it for now. This would in turn break other posts, but should be the less wrong solution.
The longer term solution is probably to either find a way to limit the LaTeX2HTML functionality to selected scopes, or find a smaller plugin that does only LaTeX and nothing else, and delegate the other useful functionalities (e.g. footnotes) to other plugins.
Anyways, this again brings up the decade old question about the separation of content and style, which is often no longer a concern but is still somewhat relevant when you want to manage a traditional, content-based blog. It seems that any deviation from “plain old HTML” requires extra maintenance, which is annoying.
But I don’t need to fix everything in one go, so that’s it for now.
By the way, the author of LaTeX2HTML had been maintaining the plugin for years, and is responsive to bug reports. I sincerely thank their efforts, regardless of what solution I will adopt.