[DiapDealer]

I think it's the <p> tag that is nested in the <li> tag. It's not really necessary.

Changing the code from:

<ul class="itemizedlist">

  <li class="listitem">
    <p>Item1</p>
  </li>

  <li class="listitem">
    <p>Item2</p>
  </li>

  <li class="listitem">
    <p>Item3</p>
  </li>

  <li class="listitem">
    <p>Item4</p>
  </li>

</ul>

To:

<ul class="itemizedlist">

  <li class="listitem">Item1</li>

  <li class="listitem">Item2</li>

  <li class="listitem">Item3</li>

  <li class="listitem">Item4</li>

</ul>

Seems to work as expected in both the epub and the resulting mobi.