When cloning an existing form, when does the page title change automatically?

I've cloned a number of forms. It seems that sometimes I need to manually go to the settings section and click "show more options" to show the page title and change the page title. Other times, it seems that when I change the title of the form at the top of the page settings, the page title in the show more options section is already updated. Why?

What you are describing are the two options of changing cloned forms. You can either change it on the header or in the settings page title section. This means whichever option you choose the system  implementing the changes on the same element .