very similar to the russian issue
We have discrepancy in Polish between Linux and Windows
Run this command in both Linux and WIndows version
import locale
import datetime
locale.setlocale(locale.LC_ALL, "pl_PL")
datetime.datetime.strptime('2021-grudnia-17','%Y-%B-%d') #works only in Linux
datetime.datetime.strptime('2021-Grudzień-17','%Y-%B-%d') #works only in Winods