This is strange - the menu works fine in Chrome on desktop, and on Safari on Mobile - but users who have installed the Chrome browser on their iPhones experience this:
On the site, www.shh.org - the menu shows fine, but when you tap on the hamburger menu, the menu open, but immediately selects the first menu item making it impossible to select anything else in the menu…
I found another post about this, and it happens on webflow servers, and exported script - I’m suspecting a bug with Chrome on mobile…
I’ve had that happen as well. I think it’s because of the menu coming out over the top of the hamburger. If you pushed the menu down then it would probably remove the issue. Otherwise maybe look at your z-index settings.