At first I was afraid it was the usual general news article just made to clickbait with more imprecisions and plain ignorance than one could point a finger at, I'm pleasantly surprised to see it is just a generally faithful reporting of the news. TL;DR: for years we thought Fomalhaut B was one of the very few exoplanets we had a direct image of, turns out it was not a planet but the aftermath of a collision between planetesimals who slowly expanded and faded away over time. Bummer.
I saw a bird. Then it was not there. Bird death-rays confirmed!
On a more serious note - I expect this will happen a lot with previously discovered exoplanets as the technology advances, we may find out that some "confirmed" exoplanets were just a fluke, but in return find new ones and confirm some that were already known.
It's the nature of science.