FYI, the contents of the SecureBoot efi variables show that SecureBoot is not enabled on this system at the time this was run. And the efibootmgr output shows that grub is being booted directly, not going through shim-signed, which would not be valid if SecureBoot is enabled. So it looks like this is a problem with shim+grub not being configured correctly on installation.
FYI, the contents of the SecureBoot efi variables show that SecureBoot is not enabled on this system at the time this was run. And the efibootmgr output shows that grub is being booted directly, not going through shim-signed, which would not be valid if SecureBoot is enabled. So it looks like this is a problem with shim+grub not being configured correctly on installation.