adding a security banner key file in /etc/dconf does not work after latest update

[May Moftah]

Applying the gdm setting for enabling the security banner on the greeter on login screen has no effect after the latest update.

When applying this via gsettings or through creating files in /etc/dconf/db/gdm.d , no changes are visible on the login screen.

Running gsettings get for the key banner-message-enable and banner-message-text prints out the message we have assigned in our key file, and shows that the banner message is enabled (true) but nothing is visible on the login screen even after logging out/restarting services/rebooting.
---
ApportVersion: 2.20.9-0ubuntu7.1
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2018-05-31 (0 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
Package: gdm3 3.28.0-0ubuntu1
PackageArchitecture: amd64
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Tags: bionic
Uname: Linux 4.15.0-22-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1774215

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[May Moftah (spuersinnx)]

apport information

[May Moftah (spuersinnx)]

apport information

[Tim Lunn (darkxst)]

What did you upgrade from? I think the banner would be set in /etc/gdm3/greeter.dconf-defaults these days

[May Moftah (spuersinnx)]

We installed 18.04 on our test machines, after erasing 16.04.
We tested setting the security banner on 05-17-2018 by using dconf key files, and that worked (we had tested changing the greeter.dconf-defaults as well but that didn’t change anything).
After applying the security updates for 18.04, the changes disappeared. We recompiled all of our custom dconf settings and the only one that applied properly was the user local desktop background, even though (gsettings get) command shows that the key is set for banner-message-enable to true and banner-message-text to our desired text.