lxqt-config-session / User Directories does not show previously set xdg user dirs

I have my personal data in a separate partition, and when I do a new install of a distro
(Originally Ubuntu, then Lubuntu for a long time, now Lubuntu Next) always change xdg's user-dirs.dirs to point at directories in my partition:
"
#XDG_DESKTOP_DIR="$HOME/Desktop"
#XDG_DOWNLOAD_DIR="$HOME/Downloads"
#XDG_TEMPLATES_DIR="$HOME/Templates"
#XDG_PUBLICSHARE_DIR="$HOME/Public"
#XDG_DOCUMENTS_DIR="$HOME/Documents"
#XDG_MUSIC_DIR="$HOME/Music"
#XDG_PICTURES_DIR="$HOME/Pictures"
#XDG_VIDEOS_DIR="$HOME/Videos"
#
XDG_DESKTOP_DIR="/data/scott/Desktop"
XDG_DOWNLOAD_DIR="/data/scott/Downloads"
XDG_TEMPLATES_DIR="/data/scott/Templates"
XDG_PUBLICSHARE_DIR="/data/scott/Public"
XDG_DOCUMENTS_DIR="/data/scott/Documents"
XDG_MUSIC_DIR="/data/scott/Music"
XDG_PICTURES_DIR="/data/scott/Photos"
XDG_VIDEOS_DIR="/data/scott/Videos"
"

and yet, when I explored the preferences apps for LXQt, and visited Session Settings ->
User Directories, I found them all pointing to /home/scott/... , not /data/scott/...

This confused me, and I did some research, as I was unsure what this app was supposed to
accomplish in the first place.

It seems that this app is supposed to do conveniently with a GUI,
what I had been doing manually with just my text editor - to SET the xdg user dirs.
I have used/re-booted Lubuntu Next a number of times, and since xdg-user-dirs-update
supposedly runs "very early in the logon process" (or similar wordage), I had to
conclude one of two things:
1. Somehow xdg-user-dirs-update was not being run at all, or
2. user-dirs.dirs was not being read upon Session Settings being launched
(or at least was not populating the forms with the read file contents.)

1. seems false, as Nemo File Manager correctly finds my desktop and places it in the left panel, and the desktop itself, which is (I believe) handled by PCManFM, shows my desktop icons. (I see PCManFM itself seems to have a problem with my user dirs, as when I click on the desktop left-panel icon, I get an error: "Error when getting information for file “/home/scott/"/data/scott/Desktop" ”: No such file or directory", which I will report separately...)
PCManFM DOES find the user-dirs and populates the left panel/bookmarks with my selected directories (aside from the above error).

---------------------------------------------------------------
scott@scott-ASUS-M2N68-AM-PLUS:~$ uname -a
Linux scott-ASUS-M2N68-AM-PLUS 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:16:15 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
scott@scott-ASUS-M2N68-AM-PLUS:~$ lsb_release -dsc
Ubuntu 18.04 LTS
bionic
scott@scott-ASUS-M2N68-AM-PLUS:~$ echo $DESKTOP_SESSION
QLubuntu
scott@scott-ASUS-M2N68-AM-PLUS:~$ apt-cache policy lxqt-session
lxqt-session:
  Installed: 0.12.0-5
  Candidate: 0.12.0-5
  Version table:
 *** 0.12.0-5 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

---------------------------------------------------------------

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: lxqt-session 0.12.0-5
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: LXQt
Date: Thu May 3 14:51:45 2018
InstallationDate: Installed on 2018-04-29 (3 days ago)
InstallationMedia: Lubuntu-Next 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180421)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: lxqt-session
UpgradeStatus: No upgrade log present (probably fresh install)