alerts on calendar switch when I set first alert for 30 min and second alert for 1 hour, when I go to save it reverses the alerts making the hour alert useless

Like title states Why do my alerts on calendar switch when I set first alert for 30 min and second alert for 1 hour, when I go to save it reverses the alerts making the hour alert useless.

When I setup an alert for an event, the first one is an hour before event and the second alert is 15 or 30 mins before event, when I save it switches the alerts so the first one is 30 mins then second is an hour, by the time the 30 minute alert goes off, the second alert won't happen until after the event time. Why does it switch the alerts. this has been happening for years, since my iPhone 4, brand new iPhone 7 iOS 10 and it's still happening. WHY ISNT THIS FIXED??

so annoying