A keyboard's lighting can change because another application is allowed to control it. If the keys still work normally, investigate who owns the lighting effect before resetting the accessory or reinstalling all of its software.

Use a compatible device shown in Windows 11 Dynamic Lighting. Record the current USB port, the lighting you expect and the application that seems to trigger the change. A short sequence such as desktop, game open, game minimised is more useful than a single photograph.

Trace the control priority

Open Settings, Personalization, Dynamic Lighting. Compatible devices appear as cards. A device's individual settings override the global settings, so inspect its card when one accessory behaves differently from the rest.

The option Compatible apps in the foreground always control lighting lets an active application take over. Microsoft says the background lighting resumes when that app is minimised or closed. Decide whether you want this behaviour before changing the switch.

Under Background light control, registered ambient controllers are prioritised by their order. Dragging the intended controller to the top gives it priority. Microsoft identifies a higher-priority background controller as a possible reason the Windows brightness and effects sliders appear ineffective.

Note the original order before moving anything. Change either foreground permission or background priority first, so you can tell which control explains the result.

Rehearse the transition

Set a simple, easily recognised effect at a comfortable brightness. Open the application involved, bring it to the foreground, then minimise and close it. Compare the observed sequence with the behaviour you selected.

Check a second accessory only if it is meant to follow the same arrangement. A deliberate individual override can explain a difference without indicating that either device is broken.

Keep the connection port unchanged during the test. Microsoft notes that ambient background settings are associated with both the device and its port; moving it to a different USB port can make it appear as a different device for those settings.

When the sequence works, retain the priority order and port in the setup note. If it still fails, report the detected device, active controller and exact transition. Resetting all effects before collecting that evidence would hide which control was responsible.

Sources: Microsoft Dynamic Lighting controls.