  Based on numerical modeling with the diffusive Giesekus constitutive
equation, a recent Letter [Phys. Rev. Lett. 120, 138002 (2018),
arXiv:1801.08798] claimed that the experimental reports of shear banding in
entangled polymeric fluids were due to the disturbances from the sample edge.
The conclusion that true bulk shear banding is precluded in the presence of
edge effects is at odds with many past experimental, theoretical, numerical,
and computer simulation studies. We briefly discuss some problems of this work.
