Kyle,
Cleared the cache, tried it on multiple phones and the drop down still will only work if you load the page quickly and hit the menu before scrolling anywhere else.
I have deactivated all plugins with the exception of REV slider. Still the same issue. I strongly believe this issue is caused by the rev slider. As when the slider wasn’t installed, the home page nav worked fine. Additionally all the pages without the slider do not show the same error
Let me know advice on next steps.