In Ubuntu 19.04, when I set Bluetooth to "off" in settings, it's on again after reboot. After reading similar questions I have not found a proper solution that integrates with the settings user interface.
I have tried "sudo systemctl disable bluetooth.service". This will keep bluetooth off after reboot but does not let me turn it on again within the settings user interface. Also the settings user interface thinks bluetooth is still on does not work correctly.
I would rather not have to fix this issue with scripts.