Hebrew birthday
When I add a second (lunar) Hebrew birthday to a contact, the Hebrew birthday is displayed wrongly in the calendar. For example, I added a Hebrew birthday for 23 Oct 1999 (which is equivalent to the Hebrew date 13 Cheshvan 5760). Now his next birthday is displayed in the calendar as 13 Feb 2018 and his age is shown as 7,777 years.
Is it a bug in iPhone or can it be resolved by some setting / configuration change ?
iPhone 7 Plus, iOS 11.2