I too can confirm that the solution Florian posted (modifying /lib/udev/rules.d/97-hid2hci.rules) works.
Dell Latitude E6400, Ubuntu-Mate 18.04LTS with generic kernel (Linux 4.15.0-43-generic), udev/systemd version 237-3ubuntu10.11, bluez version 5.48-0ubuntu3.1
I too can confirm that the solution Florian posted (modifying /lib/udev/ rules.d/ 97-hid2hci. rules) works.
Dell Latitude E6400, Ubuntu-Mate 18.04LTS with generic kernel (Linux 4.15.0-43-generic), udev/systemd version 237-3ubuntu10.11, bluez version 5.48-0ubuntu3.1