  Recent measurements using catalogues of quasars and radio galaxies have shown
that the dipole anisotropy in the large-scale distribution of matter is about
twice as large as is expected in the standard $\Lambda$CDM model, indeed in any
cosmology based on the Friedman-Lema\^itre-Robertson-Walker (FLRW) metric. This
expectation is based on the kinematic interpretation of the dipole anisotropy
of the cosmic microwave background, i.e. as arising due to our local peculiar
velocity. The effect of aberration and Doppler boosting on the projected number
counts on the sky of cosmologically distant objects in a flux-limited catalogue
can then be calculated and confronted with observations. This fundamental
consistency test of FLRW models proposed by Ellis & Baldwin (1984) was
revisited by Dalang & Bonvin (2022) [arXiv:2111.03616] who argued that redshift
evolution of the sources can significantly affect the expected matter dipole.
In this note we demonstrate that the Ellis & Baldwin test is in fact robust to
such effects, hence the > 5$\sigma$ dipole anomaly uncovered by Secrest et al.
(2021, 2022) [arXiv:2009.14826, arXiv:2206.05624] remains an outstanding
challenge to the $\Lambda$CDM model.
