Capslock disables Numlock on login screen

[Claude Boellinger]

Version :

Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic
It's a Lubuntu flavor

Steps to reproduce :

Boot
Login with your user+password
Do stuff
Hit the numlock key to enable num lock (it should show on your keyboard)
Lock the screen/change user to go back to the login screen
Be sure the numlock is active
Hit capslock => NUMLOCK DISABLES!
Hit numlock => numlock reappears
Hit capslock several times => NUMLOCK STAYS!

Expected :

Caps lock shouldn't change numlock's state...

Additional info :

I have numlockx installed
I have gnome-tweak-tools installed with a caps lock behaviour set to "caps lock toggles caps lock (all keys)"

Apparently this is a sort of bad light on keyboard info : https://askubuntu.com/questions/774251/numlock-capslock-lights-wrong-after-lubuntu-wake-up

Thank you!