The Cosmic Microwave Background (CMB) spectrum, as measured by COBE/FIRAS, is the most perfect blackbody observed in nature, with spectral distortions constrained to $|y| < 1.5 \times 10^{-5}$ and $|\mu| < 9 \times 10^{-5}$. However, $\Lambda$CDM predicts small but non-zero distortions from processes like Silk damping, reionization, and the cooling of baryons, which remain undetected. More significantly, the ARCADE 2 experiment detected a strong isotropic radio background excess at low frequencies (< 3 GHz) that cannot be explained by known extragalactic sources or standard spectral distortions, creating a tension between the perfect blackbody at peak frequencies and the significant excess in the radio tail (Fixsen et al. 1996; Seiffert et al. 2011).