Created attachment 125290 [details]
Pic above: Night mode is off. "Apply" button is off
Pic below: Night mode is on. "Apply" button is still off. No reset button active
In "system settings", "Night Colour" doesn't keep the setting whengoing back to the main system settings panel. Also, after clicking on "reset", the "Apply" button stopped working.
STEPS TO REPRODUCE
1. Go to "night colour" in system settings
2. Play around with the colour temperature and the "operation mode"
3. Click "apply" then go back to the main system setting menu
The night colour set is not kept (N.B. it's 21:35 at the time I am playing with this setting)
The screen temperature and the mode should be set and kept
KDE Neon: 5.17
KDE Plasma Version: 5.17.5
KDE Frameworks Version: 5.66.0
Qt Version: 5.13.2
PC: Latitude E5570
*** This bug has been marked as a duplicate of bug 411584 ***