Steps to reproduce the issue

I noticed some strange behavior on a clean installation of Joomla 6.

1. Go to Main Menu → Home (the default menu item for the homepage).

2. Click the Blog Layout tab.

3. The first field Select Categories already contains the option All Categories.
   → Articles are displayed correctly on the homepage.

4. Remove the All Categories option and select a specific category, then save.
   → Articles from that category are displayed correctly on the homepage.

5. Remove the specific category and manually select All Categories again from the dropdown, then save.
   → No articles are displayed on the homepage.

6. Remove the All Categories option completely (leave the field blank), then save.
   → Articles are displayed correctly again on the homepage.

Expected result

Selecting All Categories manually should behave the same way as leaving the field blank.

Actual result

So, when ‘All Categories’ is manually selected, no featured articles are displayed — but when the field is left empty, everything works as expected.

System information (as much as possible)

Additional comments

Tested on a clean Joomla 6 installation, with the default Cassiopeia template and sample data.
No extensions or overrides installed.