Gnome Lock screen shows old screen before lock screen

[Mike Bernson]

I have a laptop with led backlight.

When the locking the screen and then hitting return key the old screen(screen before lock) is displayed for a short period then the lock screen is displayed. I assume this is because if I
had an older style backlight the delay would be happing while the backlight is warning up.
Since this is an led backlight there is no warm up (delay) between turning on the screen backlight
and the display showing.

This is a also a security problem because any person walking up to the lock laptop can see what
was on the screen before locking without a password.

If need I can record the whole thing with my smart phone to show the security issue.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.3-1ubuntu1~20.04.2
ProcVersionSignature: Ubuntu 5.4.0-40.44-generic 5.4.44
Uname: Linux 5.4.0-40-generic x86_64
NonfreeKernelModules: zfs nvidia_modeset zunicode zavl icp zcommon znvpair nvidia
ApportVersion: 2.20.11-0ubuntu27.3
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Thu Jul 16 17:02:59 2020
DisplayManager: gdm3
InstallationDate: Installed on 2020-03-30 (108 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
RelatedPackageVersions: mutter-common 3.36.3-0ubuntu0.20.04.1
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1532508, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.

[Mike Bernson (mike-mlb)]

I do not think this is the same problem.

1532508 is supsend issue.
This does not require supsend.

Just do nothing for the amount of time it takes to cause the screen to lock because of being idle.
then hit the return key and you see the old screen before the lock and some short time later the
lock screen displays.

[Daniel van Vugt (vanvugt)]

I think bug 1532508 has been around for so long that it's now about any case in which the lock screen is used.