In iOS 9 my clock alarms repeated for an hour but in iOS 10 only play twice. My iPhone 6plus is so big and heavy it pulls my pants down if I wear it in a belt holster, so I often set it on the table.
I have a critical health condition requiring different medications every 3 hours. If I am out of the room or more important when I am asleep, I don't always hear the first or second play of the alarm. It repeats but only one time, and when sleeping, that is often not a long enough play.
In iOS 9, it played up to an hour and I found that necessary and extremely useful. When we went from iOS 7 to iOS 8, the same thing happened and a lot of people complained and it was fixed in the first iOS 8 update.
Can you fix it in the iOS 9 update so it repeats many more times. People usually use this to wake them and twice is not enough if you are in a deep sleep then.