In less than a century? Seems really, really unlikely.

First, a century seems inconceivably fast to completely block out the light of a star, even for a hugely advanced civilization.

But suppose this were true. We’d have to be really, really lucky to see this even once because it would only happen once in a solar system’s evolution. And yet we’re talking about this happening to one hundred stars in less than a century!

Extend this back a million years — that would be over a million stars that we could see that would have winked out. Given that the Earth is a billion years younger than most stars in the solar system

It’s much, much easier to believe that some of these observations were mistaken, or that there are natural forces at work here (e.g. dust clouds “temporarily” obscuring stars for just a centuries) than hordes of super-intelligent races taking their stars offline in the twinkling of a cosmic eye.