Sub-page display works on desktop but not on tablet

I don’t know whether or not it has anything to do with my upgrade today to 3.5.1 but when I wanted to add some detailed information to my website: https://www.carolinahappytails.com I created a blank page named “Details” and added two sub-pages to it. On my desktop, when I mouse over the “Details” menu item, the names of the sub-pages show up as expected and display correctly when clicked. On my tablet however, the names of the sub-pages appear very briefly, then disappear. Can someone tell me what’s happening?