The ASR–Mother Wave Framework predicts a cosmic birefringence angle β_ASR ≈ 0.190°, slightly below the range β_observed ≈ 0.20°–0.35° reported by the Atacama Cosmology Telescope. This note proposes that the discrepancy is not a failure of the framework but a structurally expected consequence of observer embedding: in a universe governed by the axiom U = F(U), the observing apparatus is itself a node of the same harmonic spiral whose phase rotation it is attempting to measure. The ASR Observer Postulate is introduced, formalising the correction factor δβ(n_obs) and its connection to the relativistic principle of no privileged observer.