Category page "posts loop" has "no posts to display"/fewer for some categories

Theme: Newspaper 12.4
Templates used: Magazine Pro
Template I’m seeing this problem: Category Template – Magazine PRO
Wordpress: 6.2.2 (latest)
PHP: 8.1.19 (also tested with PHP 7.4.33)

I can provide URLs/login in private message as needed.

I have a hierarchical category tree. Example:
Animals – Birds – Blue birds (3 posts)
Animals – Birds – Red birds (7 posts)

For this example, I have a post titled “Mountain bluebird” that is a member of (at least) 3 categories, ie “Animals”, “Birds” and “Blue birds”.

If I look at the category page for “Animals” I will see the post about the mountain bluebird.
If I look at the category page for “Birds” I will see the post about the mountain bluebird.
However, if I look at the category page for “Blue birds” I only get “No posts to display”, even if there are 3 posts with that category set.

Strangely enough, this problem is only partially there with the “Red birds”-category. In there I can see 3 of the 7 posts with that category.

The block that is failing is the “Posts loop”-block, which is standard on the “Magazine PRO” template.

If I clone the template, and add a “Flex box 1” with filter set to “Current category” that flex box will get the articles without any problems. But the Posts loop still displays “No posts to display”.

This is a fairly fresh install (last week) where I imported all posts from the current site, as well as imported the “Magazine pro” templates.

Thank you, you are absolutely right. I see that the “magazine pro” template has a “Big grid flex 1” on top that pulls articles from all categories, so I assumed the posts loop below would start with the current category first post, but it has indeed an offset of 4.

Thank you so much!