Google is really shady. So whenever we use the share button on YouTube, they add a code to the end of the link that offers no benefit to us, but allows Google to tie your machine as source who shared the link that others click on. When you look at the link that you posted, you'll see the letters SI in it and after that, you see the tracker.

To work around this, on desktop, you can copy the link from the address bar, which won't include the code. Also, Firefox has a feature to copy links without trackers in them, because the practice is pervasive. On mobile, I would recommend just backspacing the junk in hopes of protecting your privacy a tiny bit.