Also I don't know which language you are using, however you can change the language for the user like:
Check the language that has the first date Monday... more correct check the value of the DateFirs col, that is third col in your results. is it 1!
SELECT * FROM sys.syslanguages
Then, now try to change the language of the user that you've created to run schedule jobs, like this:
USE [master]
GO
ALTER LOGIN WITH DEFAULT_LANGUAGE = "Your language that you have choose to be from syslanguages"
GO
Sample:
USE [master]
GO
ALTER LOGIN [YourUserName] WITH DEFAULT_LANGUAGE = [Deutsch]
GO