Ln a recent paper, Kladko ct al. (Phys. Rev. Lett. 84 (2000) 4505) studied front propagation failure in lattices of nonlinear diffusively coupled cells. This phenomenon is revisited here and associated with a saddle-node infinite period bifurcation. The results are used to compare existing theories on Goldstone modes and Peierls-Nabarro barriers for parabolic and hyperbolic systems. (C) 2001 Published by Elsevier Science B.V.