  Dorn-Wallenstein, Levesque, & Ruan recently presented the identification of a
z=0.215 active galaxy located behind M31 and claimed the detection of multiple
periodic variations in the object's light curve with as many as nine different
periods. They interpreted these results as evidence for the presence of a
binary supermassive black hole with an orbital separation of just a few hundred
AU, and estimated the gravitational-wave signal implied by such a system. We
demonstrate that the claimed periodicities are based on a misinterpretation of
the null hypothesis test simulations and an error in the method used to
calculate the false alarm probabilities. There is no evidence for periodicity
in the data.
