  In a recent paper (arXiv:1701.04298 [quant-ph]) Toro\v{s}, Gro{\ss}ardt and
Bassi claim that the potential necessary to support a composite particle in a
gravitational field must necessarily cancel the relativistic coupling between
internal and external degrees of freedom. As such a coupling is responsible for
the gravitational redshift measured in numerous experiments, the above
statement is clearly incorrect. We identify the simple mistake in the paper
responsible for the incorrect claim.
