  The recent paper cited above claims that a molecular simulation of one
specific model of supercooled water establishes a stable interface separating
two metastable liquid phases, which would imply the existence of metastable
two-liquid criticality for that model. Here, we note that this claim conflicts
with fundamental principles and with earlier work published in the
\textit{Journal of Chemical Physics}, and we show that the claim is unjustified
by the data put forward to support the conclusion. Other technical problems are
also noted.
