First time that I heard of this problem. Create a brand new user and log in. If it works for this new user, the problem is in your setup, like an extension clash.
I am having the same and a similar issue on Fedora 42.
GNOME version: 48.4
Wayland
CPU: AMD Ryzen AI 7 300 series
GPU: AMD Radeon 860M Integrated Graphics
Framework 13 laptop with 2.8k display
On my main user account, Night Light works for about 5 seconds before fading back to how it was. The slider stays in place, but the effect fades away. I am using a custom color profile under Color Management.
On a brand new guest user account, Night light does not work at all. I am using the “Automatic - Built-in display” color profile under Color Management.
Might have to go searching for an extension to make up for this in the meantime.
Ok, so there’s a GNOME extension called Bedtime Mode (Bedtime Mode - GNOME Shell Extensions) which has an option in settings for “Amber.” It’s not perfect, but it’s close enough to get the job done.
enable night light and it started working immediatelly
log back to my main account and night light started to work immediatelly too.
before that, reboot hasnt helped, nor toggling the settings. what caused it to work again after creating new user, i am not sure. I am just glad it started working again.
reproducing the exact same behaviour - created a temporary test account and was able to regain night light functionality, though this ended following the test accounts removal + system reboot.
Is there a way to capture debug information from gnome shell regarding the inability to activate this feature? Should we file this issue as a new ticket since it cropped up for us with Fedora 43 + GNOME 49/49.1?