I have reproduced the problem with grub2 (2.02-2ubuntu8.20) w/ this layout:
/boot/efi
/ xfs
I then boot with a live cd, mount the partitions, mount --bind {dev, proc, run, sys} and chroot to enable proposed and update grub to version 2.02-2ubuntu8.21 and grub2-signed (1.93.24)
And now everything is working fine, and I can no longer reproduce the problem.
[VERIFICATION BIONIC]
I have reproduced the problem with grub2 (2.02-2ubuntu8.20) w/ this layout:
/boot/efi
/ xfs
I then boot with a live cd, mount the partitions, mount --bind {dev, proc, run, sys} and chroot to enable proposed and update grub to version 2.02-2ubuntu8.21 and grub2-signed (1.93.24)
And now everything is working fine, and I can no longer reproduce the problem.
- Eric