It’s the IE effect in more ways than one. Apple makes money from apps, and by having a monopoly on which app store you can use. Therefore it’s in their interest to nerf the browser as much as they can get away with it, and why they force third party browsers to use the Safari rendering engine under the hood.
CF’s captcha works by activating obscure browser features banking that bots haven’t implemented them or behave just differently enough to stick out as unusual. Try creating a new profile with default settings, and if that works try adding your customizations back one by one until you find the one breaking CF.