Summary:

Pages whose storage XHTML contains a <pre> element nested directly inside another <pre> element fail to load in view mode with IllegalStateException: Found unhandled xhtml events .... Editor mode loads fine and silently normalizes the content on save. Other block-level constructs inside <pre> (paragraph, list, table) are tolerated. Minimal reproducer is <pre>...<pre>...</pre></pre>. Confirmed by section-level and construct-level bisection on a test instance.

Steps to reproduce:

 1.  Create a page via storage REST API with body containing <pre>...<pre>...</pre></pre>.
 2.  Open in view mode → fails with the unhandled events exception.

Expected:

Renderer should tolerate or gracefully degrade malformed nested <pre> instead of failing the entire page render. 

Workaround:

Edit the page storage to replace <pre><p>...</p><pre>...</pre></pre> with <p>...</p><pre>...</pre> (paragraph + standalone <pre>). Saving via the modern editor or storage REST API restores rendering.