Bug#868358: mate-screensaver thinks it's activated but doesn't appear to have locked the screen

[Brett Parker <iDunno@sommitrealweird.co.uk>]

Package: mate-screensaver
Version: 1.20.0-1
Followup-For: Bug #868358

Dear Maintainer,

   * What led up to the situation?

Enabled mate-screensaver as part of session...

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

Locked the screen, came back and it was not locked, however:

$ mate-screensaver-command --query
The screensaver is active
The screensaver is not inhibited
$ 

   * What was the outcome of this action?

On first lock, the screensaver appears and runs with locking for some period of
time, however after around an hour (maybe less) it stops actually locking the
screen, and the screensaver entirely disappears, but mate-screensaver-command --query
thinks that it's still active.

   * What outcome did you expect instead?

That when mate-screensaver-command thought the screensaver was active that,
err, the screen would actually be locked.

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.16.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages mate-screensaver depends on:
ii  dbus-x11                  1.12.8-2
ii  libatk1.0-0               2.28.1-1
ii  libc6                     2.27-3
ii  libcairo-gobject2         1.15.10-3
ii  libcairo2                 1.15.10-3
ii  libdbus-1-3               1.12.8-2
ii  libdbus-glib-1-2          0.110-2
ii  libgdk-pixbuf2.0-0        2.36.11-2
ii  libgl1                    1.0.0+git20180308-3
ii  libglib2.0-0              2.56.1-2
ii  libgtk-3-0                3.22.29-3
ii  libice6                   2:1.0.9-2
ii  libmate-desktop-2-17      1.20.1-2
ii  libmate-menu2             1.20.0-2
ii  libmatekbd4               1.20.1-1
ii  libnotify4                0.7.7-3
ii  libpam0g                  1.1.8-3.7
ii  libpango-1.0-0            1.42.0-1
ii  libpangocairo-1.0-0       1.42.0-1
ii  libsm6                    2:1.2.2-1+b3
ii  libstartup-notification0  0.12-5
ii  libsystemd0               238-5
ii  libx11-6                  2:1.6.5-1
ii  libxext6                  2:1.3.3-1+b2
ii  libxklavier16             5.4-3
ii  libxss1                   1:1.2.2-1+b2
ii  libxxf86vm1               1:1.1.4-1+b2
ii  mate-desktop-common       1.20.1-2
ii  mate-screensaver-common   1.20.0-1
ii  mate-session-manager      1.20.0-1

Versions of packages mate-screensaver recommends:
ii  mate-power-manager  1.20.1-1

Versions of packages mate-screensaver suggests:
pn  rss-glx            <none>
pn  xscreensaver-data  <none>

-- no debconf information