This question has this block of HTML:
<h4 class="toggle">Title1</h4>
<h4 class="toggle">Title2</h4>
<h4 class="toggle">Title3</h4>
<div class="container">Content1</div>
<div class="container">Content2</div>
<div class="container">Content3</div>
Which is rendered with these strange colors:
There's another JavaScript code block on the page. I'm not sure if the bug would show itself were that other block removed, since the highlighter isn't working during preview for me.