Occasionally I will be reading a website and then try to scroll down, but my screen will be stuck. Totally frozen. For several seconds I can't scroll up/down/left/right. I can quit the browser, it isn't like my whole phone is locked up but this happens on several browsers. Not just Safari. This has been happening ever since I got the phone and three iOS updates haven't cured it, nor have clean installs etc. It doesn't happen all the time but it can happen on any website. There appears to be no rhyme or reason to it.