This documentation is not using furo.css as the stylesheet. If you have set html_style in your conf.py file, remove it.

[kss149]

I am getting this error since the 2023.08.17 release:
Handler <function _html_page_context at 0x7f93c8af77a0> for event 'html-page-context' threw an exception (exception: This documentation is not using `furo.css` as the stylesheet. If you have set `html_style` in your conf.py file, remove it.)

I haven't set html_style in my conf.py file.
I have:

html_static_path = ["_static"]
html_css_files = ["custom.css"]

So I'm struggling to understand what the issue is.