According to this article: "The recorded dips were ragged and irregular, sometimes shallow but sometimes blocking up to 20% of the star's light — and their timing was unpredictable."
I'd personally be more convinced it is something alien if the waveform in the article looked something like a square wave (defined) and was consistent in amplitude and frequency.
Bingo. They see something happening, something we have not previously observed, and that is all they know. Everything else is pure speculation. I hope it is aliens, I hope they have made a Dyson sphere around a star or are feeding a black hole and skimming electrical power off it because that would be so amazingly cool. But that's just my wishful thinking, period, end of statement.