Grouped picklist value is not translated into French when Document language is set to French

Hi, 

We created a group copy type, group by a picklist value, this picklist label has French translation values, however when user's language is set to French, the picklist always show English. 

I tried use Excel as middleware and custom metadata type to translate, it is working for non grouped type, but not working for grouped.

Is there a way to do this translation?

Thank you,