GRUB locale broken after 2.06r499

GRUB menu IS in english instead of german when upgrading version 2.06r499…
Quick and dirty WORKARROUND:
copied this file from installed 2.06.r499… to a safe place:
upgraded to 2.12rc1:
replaced the original file by the saved file (that from 2.06.r499)
sudo update-grub
Result: GRUB-menu in geRman again

What is the disadvantage of the solution,
and who can forward the bug to the “responsible authorities”???

Is that the language of gremlins?