The Cosmological Principle – that the Universe is statistically isotropic and homogeneous – leads to a critical consistency test of the standard model of cosmology: the rest-frames of matter and the CMB must coincide. Estimates of the kinematic dipole in radio continuum surveys lead to an agreement in direction with the CMB dipole, but an anomalously large velocity. Recent estimates from the CATWise2020 quasar sample put this velocity tension at > 4 sigma. I highlight a fundamental theoretical systematic: the standard formula for extracting the velocity from the matter dipole is not correct. This may not resolve the tension, but the correct formula needs to be applied before a robust claim can be made.