Each time I restart my 2018 Mac mini running Mojave after a complete shutdown, I have to connect my Magic Keyboard (to USB) to be able to type my login/password.
Once it's done, I can unplug it and use it via Bluetooth.
Question; is it a "feature" for some security reason? Or is it a bug? (keyboard battery is at 100%). How can I get it to retain the Bluetooth connection across reboots?