Is there a Radio Excess from the Decoupling of Pre-recombination Bremsstrahlung?

Recently it has been suggested that thermal bremsstrahlung emission, when decouples prior to recombination, creates an excess over the Planck cosmic microwave background spectrum at sub-GHz frequencies. Remarkable by itself, this would also explain a long-standing unexplained deficit in predictions of extragalactic radio background. In brief note we reiterate no such non-thermal component can arise itself matter and radiation remain kinetically coupled.