Problem with headers

Hi all,

I use Automattics AMP plugin combined with Glue for Yoast SEO & AMP.
Problem: the headers of ‘color boxes’ won’t appear in the AMP-version of my articles. These color boxes are coloured asides (a special class within the theme). Example: look at the blue aside at the top of the right column in this article.

This is the code:
<div class=”bg-blue clearfix”> (= ‘start color box’)
<h3><span style=”color: #ffffff;”>header text</span></h3>
Then follows the article text and finally the </div> to end the color box.

My questions:
– why doesn’t AMP show these headers?
– how do I solve this?

(Of course I could put the header above the color box but that doesn’t look very good. I also could insert the header of the color box in plain text, but that’s not a good idea from a SEO point of view…)

Thanks for your help!

Regards,

Renske63