Switching to another layout keyboard shortcut does not work after resuming from suspended state

I am setting keyboard shortcuts using Gnome Tweaks:

Keyboard & Mouse -> Additional Layout Options -> Switching to Another layout

and choose

Alt+Shift and Alt-Space

Then the above key combinations change layout between Greek+English without a problem.

After closing the lid of the laptop and resuming, the key shortcuts do nothing. By restarting Gnome:

Alt-F2 r

the keys work again.

I have also set a different keyboard shortcut via Settings (Super-Space):
Settings -> Keyboard Shortcuts -> Typing -> Switch to next/previous input source
This shortcut is not affected when resuming from the suspended state.

See also other user's reports at:
https://askubuntu.com/questions/1248813/ubuntu-20-04-switch-between-two-keyboard-layouts-does-not-work-properly

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-tweaks 3.34.0-2ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-53.59-generic 5.4.65
Uname: Linux 5.4.0-53-generic x86_64
NonfreeKernelModules: sep5 socperf3 pax
ApportVersion: 2.20.11-0ubuntu27.12
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Fri Nov 20 15:45:26 2020
InstallationDate: Installed on 2015-12-29 (1787 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
PackageArchitecture: all
SourcePackage: gnome-tweaks
UpgradeStatus: Upgraded to focal on 2020-11-15 (4 days ago)