UNTimeIntervalNotificationTrigger with manual time change work incorrect

I add my notification with

UNTimeIntervalNotificationTrigger(timeInterval: 30*60, repeats: false)

So I expect that my notification should be delivered after 30 minutes from current time. If I change time zone on my phone - all works correct. But If I change time manually, for example + 1 hour - then my notification is delivered to me at the time of change. Is there some way to handle this behaviour or is it expected? May be there is some documentation where describe this behaviour?

Thanks in advance.