Tapping on links in one book on Kobo Forma does nothing. Can Calibre fix this?

[droopy]

There's a particular book that I'm reading right now on my Kobo Forma. The file extension is kepub.epub.

When I tap on internal links in the book (e.g. links in the Table of Contents to go to specific chapters; numerical links that should lead to pop-up notes), it doesn't work.
Here's video I took: https://i.imgur.com/lG2Y9Dm.mp4
(I added the qualification of "internal" because links to, say, the publisher's website, do work)


But on the Calibre viewer on my laptop, they work.

Other books on my Kobo Forma do not have this problem.

I use Calibre to manage my books. I use Calibre to push the books to my Kobo Forma.
How can I figure out the cause of this problem?
How can I solve this problem?

[ownedbycats]

Open eBook in the editor to the table of contents. What does the HTML code look like?

[droopy]

It looks like this:

<p class="calibre15"><span class="calibre13"><span class="italic"><a href="#filepos11115"><span class="calibre14"><span class="italic"><span class="koboSpan" id="kobo.30.1">Preface</span></span></span></a></span></span></p>
<p class="calibre15"><span class="calibre13"><span class="italic"><a href="#filepos23339"><span class="calibre14"><span class="italic"><span class="koboSpan" id="kobo.31.1">Preface to the Second Edition</span></span></span></a></span></span></p>
<p class="calibre19"><span class="calibre8"><a href="#filepos24935"><span class="calibre14"><span class="italic"><span class="koboSpan" id="kobo.32.1">Introduction</span></span></span></a></span></p>

[Quoth]

Need to see CSS for calibre15, calibre13, calibre14, calibre19, calibre8, koboSpan

I'd be surprised if <span class="italic"> does any more than an <i>

madly too complicated!

[JSWolf]

Originally Posted by droopy

It looks like this:

<p class="calibre15"><span class="calibre13"><span class="italic"><a href="#filepos11115"><span class="calibre14"><span class="italic"><span class="koboSpan" id="kobo.30.1">Preface</span></span></span></a></span></span></p>
<p class="calibre15"><span class="calibre13"><span class="italic"><a href="#filepos23339"><span class="calibre14"><span class="italic"><span class="koboSpan" id="kobo.31.1">Preface to the Second Edition</span></span></span></a></span></span></p>
<p class="calibre19"><span class="calibre8"><a href="#filepos24935"><span class="calibre14"><span class="italic"><span class="koboSpan" id="kobo.32.1">Introduction</span></span></span></a></span></p>

What this conversion from a Kindle eBook or a conversion from an ePub? If it's from ePub, then use the KoboTouchExtended driver to convert to KePub on the fly as that doesn't use Calibre to convert when it adds the code to make it into KePub.

[droopy]

Originally Posted by Quoth

Need to see CSS for calibre15, calibre13, calibre14, calibre19, calibre8, koboSpan

I'd be surprised if <span class="italic"> does any more than an <i>

madly too complicated!

Hi quoth,
here's the book, all scrambled

[droopy]

Hi Quoth,
Here's the same book, but from a better source. The problem is now resolved, with this version of the book

[Quoth]

Glad you sorted.