Ios 11.4.1 seems to have introduced some new level of protection stopping some text being copied in Safari. I am working through my Italian course on Duolingo, via Safari on my iPad, and when I had problems with grammar, etc., in a sentence, I went to the accompanying discussion and often copied the explanation into a Pages file. With the update to 11.4.1 I find I can no longer copy any text in the discussion, which is a bit annoying. Btw, this is 11.4.1 related as I can still copy on my Windows 7 PC. (I have sent a bug report to Duoling) This only seems to affect some web pages and presumably there is some flag that can be set or cleared relating to copying in the web page source or template. There is a way round it. By using the Safari ‘print to PDF, I can subsequently select and copy what I want in the PDF, paste into my file, and then delete the PDF. Longwinded, but at least it helps.