  We address the interpretation proposed in [S. H. Simon, arXiv:1801.09687] of
the thermal conductance data from [M. Banerjee et al., arXiv:1710.00492]. We
show that the interpretation is inconsistent with experimental data and the
sample structure. In particular, the paper misses the momentum mismatch between
contra-propagating modes. Contrary to the claim of the paper, low energy
tunneling involves a large momentum change. We consider only the 'small
Majorana velocity' mechanism [S. H. Simon, arXiv:1801.09687]. Other mechanisms,
interpretations of the experiment, and their difficulties are beyond the scope
of this Comment.
