Show Region if not logged in not functioning properly on one particular iPad

I've created a web app that utilizes security assist Show Region if function to determine different levels of user login and authentication. It works flawlessly across all devices and browsers, with one exception. The client has one particular iPad, I'm told an older one, for which the Show Region function doesn't seem to work. For instance, there is a login form that is set to show only if the user is not logged in, but for some reason, that login form remains hidden on that particular device even if the user is not logged in.

I'm awaiting more information on the exact iPad version, iOS version and browser, but I'm looking for direction on troubleshooting. What sorts of functionality within the device would prevent the Show Region function from operating properly? I had thought with PHP it would be primarily a server side function, but apparently there's something else to it.