With my current personal.ini I get these results. <attached> I manually put the series description into the epub's metadata then updated it again through FFF to add the series description to the title page, not sure if that's your process as well since I'm not familiar with this. I also put the composite column in titlepage_entries just to demonstrate what it'd look like if added there.
I have the series description and summary on my titlepage_end instead of titlepage_entries.
Code:
titlepage_end:
</dl>
<div class="flex-parent display-on-cover">
<div class="flex-child-edge"></div>
<div class="flex-child-text stats"><span>${rating}</span> ${icons} ${numWords} ◈ ${chapterslashtotal}</div>
<div class="flex-child-edge"></div>
</div>
<div class="flex-parent display-on-reader">
<div class="flex-child-edge"></div>
<div class="flex-child-text">${icons}</div>
<div class="flex-child-edge"></div>
</div>
<div class="tag-summary-content">${calibre_cust_seriesdesc}${description}</div>
</body>
</html>
And the relevant css for the tag-summary-content class
Code:
.fff_titlepage .tag-summary-content p {
margin-top: 0;
}