The iFrame information is not loaded in the page when the search hit link is clicked. It does load, if you further refresh the page.
The question...
Is there a way to force the inclusion of the iFrame material straightaway, perhaps something I can include in the HTML Code Object that contains the iFrame incantation on the page?
Oddly enough, there is an initial line from the embedded iFrame-d document, see below.
Here's the sequence.
1. Type the topic name into the search box (in this case, I've searched for "booleansolid" and hit #4 is the one I click on):

2. Result
The area marked by the yellow/gold rectangle is where the iFrame-drawn document is meant to go):

Note that the line containing "K4 Base Library K4 Rule Objects" and copyright IS in the iFrame-spawned content.
3. iFrame content is there after hitting F5 (refresh) in the browser:

The iFrame incantation, embedded in the topic page via an H+M HTML Code Obect:
<iframe class="x" width="100%" height="100%" style="border:0px; overflow:hidden;" onload="this.style.height=(this.contentWindow.document.body.scrollHeight+30)+'px';" src="../kbDocsAutodox/designs/booleansolid.html" ></iframe>