Thanks for the reply. Based on your test, I experimented a bit more and noticed that it works fine when you are not logged in. But it does not work when you are logged in and the black wordpress admin bar is at the top of the screen. I’m guessing there is some CSS conflict.
Also, I validated that this behavior is the same on Safari for iPad and Chrome for iPad. On both of these browsers, the menu only works properly in a non-logged in state.
As a stop-gap, I have removed the wordpress admin bar and everything works great in a logged in or logged out state. However, it might be nice to have this resolved so we could have the option of un-hiding the admin bar.