Comment 1 for bug 1781042

Seems related to this bug.
Ubuntu 18.10 Cosmic installed /EFI/grub
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1775743

As update during install creates /EFI/grub like in above install.
But some users manually boot into Ubuntu & update grub and it works.

manual boot:
grub> set root=(hd0,gpt8) #where gpt8 in example is ext4 partition with ubuntu.
grub> configfile /boot/grub/grub.cfg
https://ubuntuforums.org/showthread.php?t=2396045
$ sudo apt-get install grub-efi-amd64
$ sudo update-grub

or it seems Ubiquity installs a different version of grub during install than an update once booted installs?