On some websites if you highlight and copy a word because you want the definition or read more about it for example. Paste the word into a new tab or browser and it pastes the entire link for the article.
I dislike this behavior. It seems to be part of a more complicated way of thinking about copy and paste. But I think it works better if you copy and paste into a simple text editor, and then copy and paste from there. Or you could use a program that strips away all but the most basic information from what’s in your clipboard. I work on PCs and Macs, and on PCs I use PureText (PureText) (I have no connection to the product) which sits in the system tray and glimmers a little when you click it. Whatever is in the clipboard stays there but gets reduced to its most simple form, so you can copy and paste without the result looking like a ransom note. Sadly I don’t happen to know of a similar program for the Mac. You could also try “paste and match style” or “paste special” or something, that may fix it.
The behavior you’re seeing is often an intentional design choice by the website author. They use javascript to block the normal operation of copy/paste and impose another one designed to prevent you from copying their text uncredited. In this case, adding to it the URL. Maybe in hopes you won’t notice, or that you’ll settle for what they give you. So that instead of their words being read on someone else’s media, they’ll have to come to their website to read them, giving clicks or impressions or ad exposure or whatever.
There may be addons for browsers that counter this behavior. In my case, if I run into this, I judge whether the website is worth quoting at all, or more deserving of being ignored into oblivion. If I have to copy, temporarily turning off Javascript usually does the trick.