I don't know if this is mobile-specific, but when I open thread options in discussions list it focuses on the first option. If I click on the box title again it removes focus and finally on the second click it closes the box.
It should close the box on the first click when opened.
By the way, autofocus doesn't work, I just see that some option is selected but there are no controls to change it. Of course if I click on it controls appear.