Failed saving grub configuration on Ubuntu 21.10 - Impish Indri

[Mark Orchard]

failed running 'grub-mkconfig -o "/boot/grub/grub.cfg"' output:
Sourcing file '/etc/default/grub'
Sourcing file '/etc/default/grub.d/init-select.cfg'
Generating grub configuration file...
using custom appearance settings
Found background image: /boot/grub/themes/img19_1920x1200.jpg
wrong argument count. You have to give the config as parameter 1!
cat: write error: Broken pipe

[Daniel Richter (danielrichter2007)]

One of your /etc/grub.d/*_proxy files seems to be broken. There is a call to /etc/grub.d/bin/grubcfg_proxy which should be called with exactly one argument, but it seems like there are multiplre arguments. Maybe a shell syntax error? To let me looking for the problem, I need at least the corrupted file attached.