Selecting all descendants of a folder hierarchy in the world outliner doesnt accurately show what all is selected. This does not always occur and is a visual bug. The items in the level are still selected.
Found in 4.18 CL# 3832480, 4.19 CL# 4033788, 4.20 CL# 4302132, and 4.21 CL# 4348893
Results:
The items in the second folder will not be highlighted in the world outliner however they are still selected in the level
Expected:
The world outliner would accurately show all items highlighted
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-63845 in the post.