The meaningless kernel bug ever

[Sam Varshavchik]

I feel silly even writing this.

I just installed the 5.13.4-200 kernel update on my venerable Thinkpad W520.  
This old battle tank'd keyboard has a button that mutes the built-in  
microphone. It has a tiny orange LED that's lit when the mike is muted. I  
don't remember ever having to use it in the last decade, but it's there and  
that's what it does.

Booting the 5.13 kernel: the orange LED gets turned on during the boot, and  
it stays lit. The mute button itself is fully functional. Audio mixer  
dutifully reports the ambient noise level gets muted on/off.

There's also the built-in speaker mute button that works the same way, and  
its behavior is unchanged under 5.13, its orange LED is on only when it  
mutes the audio out.

Rebooting 5.12: both mute buttons' LED indicators work as advertised.

Can anyone think of an even more meaningless kernel bug?