bug#32068: 26.1; problem with org-agenda and categories

[rrandresf@gmail.com]

When evaluating the snippet below:
--8<---------------cut here---------------start------------->8---
(eval-after-load "org"
  '(progn
;;;; overwrite some settings
     (setq org-startup-folded nil ;unfolded
           org-agenda-show-all-dates t
           org-confirm-elisp-link-function nil ;; 4 the scratch call
           org-agenda-include-diary t
           org-agenda-include-all-todo t
           )
     (when (file-directory-p "~/docs/org/deft/")
       (setq org-agenda-files (directory-files "~/docs/org/deft/" t ".*agendatest\.org$"))
       )
     (define-key org-mode-map (kbd "M-a") nil)
     ))

(require 'org)

(funcall 'org-agenda-list)
--8<---------------cut here---------------end--------------->8---

I am getting (which is not fine):
--8<---------------cut here---------------start------------->8---
Week-agenda (W27):
Monday      2 July 2018 W27
  final:       9:00...... wc: 1eBrazil - 2fMexico (samara){16}
  final:      13:00...... wc: 1gBelgica - 2hJapon (rostov){16}
Tuesday     3 July 2018
  final:       9:00...... wc: 2eSuiza - 1fSuecia (san petersburgo){16}
  final:      13:00...... wc: 2gInglaterra - 1hColombia (moscu){16}
Wednesday   4 July 2018
  Diary:      Independence Day
Thursday    5 July 2018
Friday      6 July 2018
               0:38...... now - - - - - - - - - - - - - - - - - - - - - - - - -
               8:00...... ----------------
  final:       9:00...... wc: 1qfFrancia - 2qfUruguay (nizhny){4}
              10:00...... ----------------
              12:00...... ----------------
  final:      13:00...... wc: 5qfBrasil - 6qfBelgica (kazán){4}
              14:00...... ----------------
              16:00...... ----------------
              18:00...... ----------------
              20:00...... ----------------
Saturday    7 July 2018
  final:       9:00...... wc: 7qfRusia - 8qfCrocia (samara){4}
  final:      13:00...... wc: 3qfSuecia - 4qfInglaterra (sochi){4}
Sunday      8 July 2018
--8<---------------cut here---------------end--------------->8---

the output should be:
--8<---------------cut here---------------start------------->8---
Week-agenda (W27):
Monday      2 July 2018 W27
  8:           9:00...... wc: 1eBrazil - 2fMexico (samara){16}
  8:          13:00...... wc: 1gBelgica - 2hJapon (rostov){16}
Tuesday     3 July 2018
  8:           9:00...... wc: 2eSuiza - 1fSuecia (san petersburgo){16}
  8:          13:00...... wc: 2gInglaterra - 1hColombia (moscu){16}
Wednesday   4 July 2018
  Diary:      Independence Day
Thursday    5 July 2018
Friday      6 July 2018
  4:           9:00...... wc: 1qfFrancia - 2qfUruguay (nizhny){4}
  4:          13:00...... wc: 5qfBrasil - 6qfBelgica (kazán){4}
Saturday    7 July 2018
  4:           9:00...... wc: 7qfRusia - 8qfCrocia (samara){4}
  4:          13:00...... wc: 3qfSuecia - 4qfInglaterra (sochi){4}
Sunday      8 July 2018
--8<---------------cut here---------------end--------------->8---



In GNU Emacs 26.1 (build 2, armv7l-unknown-linux-gnueabihf, X toolkit, Xaw3d scroll bars)
 of 2018-06-28 built on sacsa
Windowing system distributor 'The X.Org Foundation', version 11.0.11903000
Recent messages:
setq: Opening directory: No such file or directory, /home/olla/doc/sorg/deft
Saving file /home/olla/docs/org/deft/jl-diary.agendatestel.org...
Wrote /home/olla/docs/org/deft/jl-diary.agendatestel.org
Preparing diary...done
Preparing diary...done
Preparing diary...done
Preparing diary...done
Preparing diary...done
Preparing diary...done
Preparing diary...done
Quit
Configured using:
 'configure '--program-transform-name=s/^ctags$/ctags.emacs/'
 --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/usr/share --with-x-toolkit=lucid
 --mandir=/usr/share/man --pdfdir=/usr/share/doc/emacs --with-modules
 --with-xft --without-gconf --without-gsettings --with-imagemagick
 --without-xwidgets --without-pop --with-gameuser=:games 'CFLAGS=-Og
 -g3' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS NOTIFY ACL
GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS
LUCID X11 MODULES THREADS LIBSYSTEMD LCMS2

Important settings:
  value of $LC_COLLATE: C
  value of $LANG: C
  locale-coding-system: nil

Major mode: Org-Agenda Week Diary Ddl Grid

Minor modes in effect:
  diff-auto-refine-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug sendmail view cal-china lunar solar
cal-dst cal-bahai cal-islam cal-hebrew holidays hol-loaddefs vc-git
diff-mode diary-lib diary-loaddefs cal-iso org-agenda edmacro kmacro
org-rmail org-mhe org-irc org-info org-gnus nnir gnus-sum gnus-group
gnus-undo gnus-start gnus-cloud nnimap nnmail mail-source tls gnutls
utf7 netrc nnoo parse-time gnus-spec gnus-int gnus-range message rmc
puny seq byte-opt gv bytecomp byte-compile cconv rfc822 mml mml-sec
password-cache epa derived epg epg-config mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader gnus-win gnus
nnheader gnus-util rmail rmail-loaddefs rfc2047 rfc2045 ietf-drums
mail-utils mm-util mail-prsvr wid-edit org-docview doc-view jka-compr
image-mode org-bibtex bibtex org-bbdb org-w3m org-element cl-seq
avl-tree generator org advice org-macro org-footnote org-pcomplete
pcomplete org-list org-faces org-entities noutline outline easy-mmode
org-version ob-emacs-lisp ob ob-tangle org-src ob-ref ob-lob ob-table
ob-keys ob-exp ob-comint comint ansi-color ring ob-core ob-eval
org-compat org-macs org-loaddefs format-spec find-func cal-menu easymenu
calendar cal-loaddefs misearch multi-isearch dired-aux cl-loaddefs
cl-lib dired dired-loaddefs elec-pair time-date mule-util tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win
x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote dbusbind inotify lcms2 dynamic-setting font-render-setting
x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 8 219191 14521)
 (symbols 24 33028 2)
 (miscs 20 118 836)
 (strings 16 70073 2629)
 (string-bytes 1 2236772)
 (vectors 12 29409)
 (vector-slots 4 704259 12516)
 (floats 8 739 501)
 (intervals 28 2244 707)
 (buffers 536 17))