This problem turned out to be an issue with the Qt version in Ubuntu 18.04.0 LTS.
Short term workaround was to remove all ‘const’ in /usr/share/deCONZ/devices/philips/0400_lightlevel.js
Long term: upgrade to Ubuntu 20.04.0 or/then to 22.04.0
If you come from 18.04.0…6 like me and experiences that keyboard and mouse do not work in 20.04.0 login screen, do this from ssh:
"sudo apt-get update --fix-missing"
"sudo apt-get upgrade -y"
"sudo apt-get install -y xserver-xorg-input-all"
"sudo reboot"
And, viola … 