Syntax errors are detected in generated GRUB config file.

After update:

# LANG=C update-grub
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-linux-lts
...
Found initrd image: /boot/intel-ucode.img /boot/amd-ucode.img /boot/initramfs-linux.img
Found fallback initrd image(s) in /boot:  intel-ucode.img amd-ucode.img initramfs-linux-fallback.img
error: syntax error.
error: Incorrect command.
error: syntax error.
Syntax error at line 325
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/grub/grub.cfg.new file attached.


This is:

# cat /etc/os-release
NAME="EndeavourOS"
PRETTY_NAME="EndeavourOS"
ID="endeavouros"
ID_LIKE="arch"
BUILD_ID="2021.08.27"
ANSI_COLOR="38;2;23;147;209"
HOME_URL="https://endeavouros.com"
DOCUMENTATION_URL="https://discovery.endeavouros.com"
SUPPORT_URL="https://forum.endeavouros.com"
BUG_REPORT_URL="https://forum.endeavouros.com/c/arch-based-related-questions/bug-reports"
PRIVACY_POLICY_URL="https://endeavouros.com/privacy-policy-2"
LOGO="endeavouros"


Do you need more information?

Thanks for help

Karsten