  De la Cruz et al. [Phys. Rev. Lett. 120, 128102 (2018); arXiv:1705.08683]
studied a noise-induced transition in an oscillating stochastic population
undergoing birth- and death-type reactions. They applied the Freidlin-Wentzell
WKB formalism to determine the most probable path to the noise-induced escape
from a limit cycle predicted by deterministic theory, and to find the
probability distribution of escape time. Here we raise a number of objections
to their calculations.
