Every time you post something to Facebook and someone else shares it, they add a tracking link. This allows them to see the history of who’s sharing what, to who and where. What’s even worse is when the link is taken outside of the Facebook environment it will still continue to track. It’s very malicious and invasive & you definitely should remove it and break the chain. One thing to note is that even by removing the tracking extension sometimes it actually still retains the code with the compromised link. A handy trick is to remove the tracking extension first, copy the new link address, paste it in the browser address bar to strip all code, recopy it and then paste that. Each tracking extension is different and this is just a general example of what one of these looks like.
The tracking code looks like this. They all start with /?fbclid=