aria-level interpretation problem

HI W3C and community,

 

Is a misinterpretation of aria-level > 6 an issue for WCAG (SC 1.3.1,
4.1.2) or a screen reader bug?

 

For a while I already wondered as a SR-user, why W3C documents flag some
notes as H2.

Now I inspected such a component at:

https://www.w3.org/TR/epub-33/#sec-intro-relations

 

In the source was no role=note but an aria-heading with an extraordinary
value for aria-level:

 

<div class="caution" id="caution-0">

<div

  role="heading"

  aria-level="31"

  class="caution-title marker">

<span>Caution</span>

</div>

 

For this component , JAWS as well as NVDA announces "heading 2" in Chrome,
Edge and Firefox, each for desktop .

 

Possible problems using higher levels are well known: 

"On elements with role  <https://w3c.github.io/aria/#heading> heading,
values for  <https://w3c.github.io/aria/#aria-level> aria-level above 6 can
create difficulties for users."

(https://w3c.github.io/aria/#aria-level)

 

So, who has to be addressed for rectification?

 

My preferred mode to get an overview and navigate documents bases on heading
hierarchy. And I know, I am not the only one.

 

Thanks,

 

Wolfgang