Leica has released a firmware update for the M11 to address issues regarding the function buttons. You can download the firmware here: Leica M11 Firmware.
Please note that after the firmware is installed, you must remove the card you have used and delete the firmware update from the card before reinserting the card and restarting the camera (or use a blank card for the update and then replace it). If a card with the update file is in the camera after the update has run, the camera will not start properly.