Hidden singularities and closed timelike curves in a proposed dual for Lifshitz-Chern-Simons gauge theories

We point out that the metrics recently proposed by K. Balasubramanian and J. McGreevy \cite{BalaMcGreevyLifshitz} as gravitational duals to Lifshitz Chern-Simons gauge theories contain both a hidden null singularity and a region of closed timelike curves accessible to asymptotic observers. Like the singularity in the original Liftshitz spacetime given by Kachru, Liu, and Mulligan, this singularity does not include large $\alpha'$ or $g_s$ corrections and hence appears to be singular in string theory as well as classically.