Accordion with javascript disabled

[gpeng]

We've come across some strange sub-heading styling on the accordion component when javascript is disabled:

The design system has no background on the headings:

[peteryates]

Interesting.

On the accordion guide page with JavaScript disabled I get no grey box around the header:

Which version of govuk-frontend are you running?

[peteryates]

Closing this for now, happy to reopen if it's definitely a form builder bug but I think it's either down to an older version of govuk-frontend or a local style.