Magic Keyboard's native function keys are not working via Bluetooth?

Instead they switch back to the function of the f1–12-keys even though that's deactivated in the preferences. Oddly enough, they are working perfectly fine when connected via a Lightning cable. I tried everything from disconnecting, debugging, restarting and crying. I found an old post in this forum discussing the same issue but it was closed due to lack of responses. So here I go again.

Anyone else still having that issue?