Blog stops loading posts on page 3

One of my blogs stops everytime on page 3 with loading new posts.
I'm using the receptar theme and have almost 100 recipes on my blog. Pagination count's good until page 3.

Checked the Grav log and Apache log but couldn't find anything which helps me to locate the problem.

How can i debug this one?

Affected website: https://www.sniederke.nl

Since pagination from page 4 and onwards does work correctly I assume there is something wrong with one of the articles or posts which are shown on page 3. Maybe something strange that should not have been copied from the original WP site.

One approach is to simply start removing articles from the last article from the bottom, then the one before that and so on until the problem goes away. Or perhaps you can spot it by looking at your source. It's probably the article with id 'post-8' since it is incomplete compared to other articles.
BTW is that Markdown or HTML?