h1 is wrapped in `header` tag even when title is provided in yaml (website project)

Hi,

I've noticed quarto is wrapping the first h1 heading into a separate header tag since version 1.6. I went through the discussion in issue #11618 and learned this is in part intended behavior. However, I think what I'm seeing might not be part of the desired functionality...

This is a minimal example:

index.qmd

::: {#custom-div}
# Div title

Some words as div's content

:::

_quarto.yml

project:
  type: website

website:
  title: 'Heading in header issue'

The output produced by quarto render on these files is

<!-- main -->
<main class="content" id="quarto-document-content">

<header id="title-block-header" class="quarto-title-block">
<h1 class="title display-7">Div title</h1>
</header>

<div id="custom-div">
<section id="div-title" class="level1">

<p>Some words as div’s content</p>
</section>
</div>

</main>
<!-- /main -->

Within the referenced issue I read something like this, where the first h1 heading is contained within a div, should not be used as the page title nor taken outside that div. This is exactly the behavior I observe when rendering a single file to html. However, when using the website project structure, and even though there's an explicit title provided for the project, the first h1 heading gets wrapped into a separate header tag and separated from the containing div in the source.

Is this intentional? Happy to help where I can.

[!NOTE]
Using quarto v1.7.32 (CLI) on debian bookworm.