Night light vs dual monitor

I am using Ubuntu on a laptop which I put in a docking station with two screens.

The night light works well when activated but after unlocking from screen saver, only the main monitor is in night light, not both.

Anyone already had that problem and found a fix ?

Thanks in advance, Lionel

This is clearly a bug. This bug report is quite similar to yours; when it's addressed that will hopefully fix our problems as well.

A workaround is to go to the Devices → Color menu in the settings and toggling color management for the problematic monitor off and on.

In https://gitlab.gnome.org/GNOME/gnome-settings-daemon/issues/6 it is recommended to run killall gsd-color. While toggling color management on or off applied only the current value running kill works throughout the phases on both monitor correctly.