[Tex2002ans]

I can duplicate this. I created another test EPUB with this code:

Spoiler:

  <p>Search for "ay" in Book View with "Current File" turned on:</p>

  <p><b>&lt;p&gt; (Pass):</b></p>

  <p>today</p>

  <p>today</p>

  <p><b>&lt;div&gt; (Pass):</b></p>

  <div>
    today
  </div>

  <p><b>&lt;p&gt; with &lt;br /&gt; (Fail):</b></p>

  <p>today<br/> today<br/> (no stop) today</p>

  <p><b>&lt;p&gt; with &lt;br /&gt; (Pass):</b></p>

  <p>todays<br/> todays<br/> (no stop) todays</p>

  <p><b>&lt;div&gt; with &lt;br /&gt; (Fail):</b></p>

  <div>
    today<br/>

    today<br/>

    (no stop) today
  </div>

  <p><b>&lt;dt&gt; and &lt;dd&gt; (Fail):</b></p>

  <dl>
    <dt>today</dt>

    <dd>today</dd>
  </dl>

  <p><b>&lt;ul&gt; (Pass):</b></p>

  <ul>
    <li>today</li>

    <li>today</li>
  </ul>

  <p><b>&lt;ol&gt; (Pass):</b></p>

  <ol>
    <li>today</li>

    <li>today</li>
  </ol>

  <p><b>&lt;blockquote&gt; (Pass):</b></p>

  <blockquote>
    today
  </blockquote>

Sigil's Book View search works fine on <p> + <div> + <blockquote> + <ul>/<ol>/<li>.

The search seems to break when:

1. The thing you are searching for is at the very end of a line
2. It is in <dt>/<dd> OR it hits a <br />

The search seems to work perfectly normal if you are searching for something like the "o" in today.