The shortcut for "Select All Descendants" doesn't select the contents in the selected folder in the World Outliner. Using the right-click method works exactly as expected.
This was reported and tested in 4.23.1 (CL-9631420). This was reproduced in 4.24.1 (CL-10757647) and Main 4.25 (CL-11115776).
Results: Folder content isn't selected.
Expected: For the contents to be selected in the World Outliner and Level
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-87523 in the post.