Some Function Keys misassigned

With the update from 1.6-6ubuntu1 to 1.6-6ubuntu1.1, some of the function keys on my device (HP Elite notebook) are misassigned. Specifically, Fn+F3 as well as Fn+F4 now toggle the microphone, while they should reduce/increase screen brightness. That worked well before the update.

Fn+F8 also toggles the microphone, which was and is correct. So now I have three function keys doing the same thing, but no function keys for screen brightness.

I'm running Linux Mint 20.3 Una 64.bit with MATE 1.26.0.

The workaround for desktop use is to add a screen brightness applet to the panel. However, that does not work for console use.