Two Birthday Alerts
Standard iOS birthday alert aside, app supports an additional birthday alert.
A) containing text "On the same day at" is app alert which can be found in
App Settings > New Events & Templates > Default Birthday Alarm
B) containing text "On day of event" is Apple's alert which can be found in
Device Settings > Calendar (or Mail, Contacts, Calendars in iOS9 and below) >
Default Alert Times (almost at bottom) > Birthdays
If there are two alerts shown, first one is ours