CSP is not working on iOS devices

I noticed today, that when I activate the CSP plugin (even If I haven’t added any policies) my website isn’t working properly on any iOS devices (iPad Air 2, iPhone 6+). I am not sure, why this happens, because if I modify the CSP by Metatag attributes, my website is displayed accurately. So I guess this is an issue of the Plugin itself. Even if I use another browser, i.e. Firefox, on an iOS device, it does not work.