Bug: Org-mode v3.8 tag hierarchy [9.3.3 (release_9.3.3 @ /home/user/.emacs.d/org-mode/lisp/)]

[Leon Weber]

Hi together, I recently updated from org-mode version 9.1.8 to 9.3. I 
noticed a problem with group tags / tag hierarchy in the agenda-view 
(Agenda for current week or day).

Example File:
--------------
#+TAGS: [ PARENT : CHILD1 CHILD2 ]
* test1 :CHILD1:
SCHEDULED: <2020-09-14 Mon>
* test2 :CHILD2:
SCHEDULED: <2020-09-14 Mon>

--------------
If I filter by the 'PARENT' tag, with the function 
'org-agenda-filter-by-tag' (in the agenda daily view) in version 9.1.8 I 
get all the child entries. In version 9.3.8 however this does not work 
anymore. Does anyone know if this is intentional? I didn't find anything 
in the release notes about this.

Tested on a vanilla Emacs installation version 26.3 and 27.1.


Emacs : GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 
3.24.22, cairo version 1.17.3)
of 2020-08-28
Package: Org mode version 9.3.3 (release_9.3.3 @ 
/home/user/.emacs.d/org-mode/lisp/)