I found a reference to the same issue from an Arch user: https://github.com/Bumblebee-Project/Bumblebee/issues/592 The workaround given was to append acpi_osi=\"!Windows 2013\" to the GRUB_CMDLINE_LINUX_DEFAULT variable in /etc/default/grub and run update-grub. After doing this, bumblebee is again able to toggle the discrete chip on and off.