Steps to reproduce the issue

Create a Module "Latest Articles and put it on the template that you can see it. Use a categorie and select "Show Main Articles" (I use the german version, not sure if they are called main articles).

Expected result

See a box with all articles from the category including main and non-main.

Actual result

Only non-main articles are showing up.

System information (as much as possible)

Joomla 3.8.11

Additional comments

It looks like it is since the latests update: 3.8.11