Islamic calendar is wrong in apple iPhone ipad and Mac

Hi. I have set up the Islamic Calendar as the alternate calendar on my iPhone and other devices. But there is a difference between the date being shown on the calendar from the actual date in my region. This is a result of difference in moon sighting in different regions.

we celebrated Eid yesterday May 2 but on my alternate Islamic calendar it’s showing today May 3. Someone please fix this and it should work according to the geographic location just like time and date for the regular calendar.