Why do the lights of keyboard turn on after standby?

What causes the keyboard to stay turned on (or turn back on a few min later) after standby and how to make it turn off on Debian? There are a few lights on my USB keyboard and for a long time after putting the computer into standby the keyboard lights went out as well. But since a few months ago, they often stay turned on or turn back on at night. One of the few bright lights on the keyboard signifies whether the numpad is active. Apparently the lights on can be different from which lights were turned on before standby. The computer is running Debian12 with KDE (this already appeared with Debian11). I don't know if this means that some components of the set-up are still running (such as the whole keyboard...and maybe the mainboard which then could theoretically send/exfiltrate data from RAM but that's another topic). **What could cause the keyboard to not shut off anymore when the computer is in standby and how to prevent this from occurring?** Any logs to check for what, is there anything I could test, or is there already a known cause and/or solution for this problem? ---- Details / full procedure: 1. Two keyboard lights are on: Function key and Numpad active 2. Putting the PC to sleep via Suspend of KDE's Power Management 3. Keyboard lights are all off for a few minutes (I'll test this further) 4. One keyboard light turns back on: Function key and if the room is dark it brightens it up (it also happened both two lights are on but I'll have to test this) 5. (Light(s) stays on for long: I'm not sure if it always stays on for many hours but last time it did stay on until I resumed the PC from sleep many hours afterwards) 6. Resume PC from sleep by pressing power button: the same two keyboard lights are turned on as before sleep Here is a similar question but unlike that user I don't have any sleep or hibernation related setting in my UEFI bios settings (nor a setting for secure boot which I think should be there) and the problem only started to occur since recently. I'll test if this also occurs when the keyboard is connected to another computer with nearly the same setup.