Why does grub2-mkconfig fails with "no command and will do nothing" error ?

Issue

• grub2-mkconfig fails to generate grub configuration file

[root@rhel8 ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
Generating grub configuration file ...
Script `/boot/efi/EFI/redhat/grub.cfg.new' contains no commands and will do nothing
Syntax errors are detected in generated GRUB config file.
Ensure that there are no errors in /etc/default/grub
and /etc/grub.d/* files or please file a bug report with
/boot/efi/EFI/redhat/grub.cfg.new file attached.

The file created /boot/efi/EFI/redhat/grub.cfg.new is an empty file.

[root@rhel8 ~]# cat /boot/efi/EFI/redhat/grub.cfg.new
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#