It's amazing how well clickbait works. I'm quite illiterate about Grin but I read a bit about it back in January when it launched and I remember the linkability issue being mentioned in a few places in the documentation. Even without that background knowledge you'd think people would be at least a little bit suspicious and curious if the sky is really falling. But no. Even though a simple google search would show that this was known pretty much since MW was "invented" in 2016.
The linkability of UTXOs (there are no addresses in Grin so "I was able to uncover the exact addresses of senders and recipients" is false right off the bat) doesn't disclose as much as the "researcher" seems to imply and there are ideas how to obfuscate the UTXOs even more. But that's not as exciting as "privacy coin broken".