GNOME does not lock screen on closing lid

[Saurav Sengupta]

Ubuntu 20.04 (Focal Fossa) (amd64 on x86_64), GNOME 3.36.1 (as reported by Settings -> About), X11, gnome-power-manager 3.32.0-2, gnome-settings-daemon 3.36.0-1ubuntu2.

On my laptop, I want to lock the screen when I close the lid. I have set HandleLidSwitch=lock and HandleLidSwitchExternalPower=lock in /etc/systemd/logind.conf. I have also set both org.gnome.settings-daemon.plugins.power lid-close-ac-action and org.gnome.settings-daemon.plugins.power lid-close-battery-action to 'blank'. However, when I log in after a boot-up and close the lid WITHOUT performing any action such as opening a shell menu or starting an application, the system does not lock the screen and I directly get back to the desktop after re-opening the lid. This continues until I perform any such action as mentioned above; after that the screen is locked on closing the lid every time as expected (until next boot).