Inconsistent mix of numerals in calendar with Arabic

MonthGrid is used to create calendar system. When switch to Ar locale, it shows inconsistent mix of numerals in calendar. All numbers are displayed in English Gregorian but texts are all in Arabic.
This works with Ja, Ko, Zh-Hk, zh-TW, He, Th, de-CH, Pt-PT, Et etc.
Attached example when you click you console displays in Arabic but calendar dates are in English.