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?