Calendar issues

I am using erpnext v12 . when I click calendar in Sales Order . it is suppose to show me the orders of the selected month, grag and replace orders or click to an empty date to add new order.
well it’s not working because I changed the language to Arabic . I tracked to issue and it was that erpnext while filtering orders it uses translated arabic dates , I managed to fix the first issue by just translating the dates back in the (get_events) function . but to create a new sales order I got this error . this is because erpnext is placing an arabic digits in the date field . I was trying all the day to find the function that trigger this or the function that validate the date so I can add some code . but I couldn’t . anyone can help .? this is a really huge bug . !
the error says (invalid date , date should be in format yyyy-mm-dd)screen|690x491