Sorting in Subfolders - Language

I am using Hazel since a long time for various tasks. One of them is sorting files into subfolders (year - month). I have several Macintoshs all set up with an English OSX - yet I've noticed that Hazel sometimes creates two folders for the months: one in English (e.g. December), the second one in German (e.g. Dezember).

Why does this happen? What should I do to have German OR English folders only?

Thanks for your hints and insight,

Thomas

Is German in your system preferences as one of the languages you want it to use? If so, do you ever switch it to be the primary one?