Currently the "List view" shows tickets in a grouped manner, if there is a partent/children relationship you'll see those tickets under the parent and not with much detials. This is part of the new Issue view released last year.

Clients are requesting issues not to be group and to show in a list manner wihout any relationshiop even if it does not have the detials you see in "details view." The clien't expedtation is to see all issues in a list not grouped together to save space.