Supplementary_AB_Systematic_Bias_Check

This work documents a systematic, boundary-induced bias that can be interpreted as a latent computational bug rather than a failure of underlying physical theory. The reported effect manifests as a phase deformation that arises at projection and boundary layers, producing apparent mode differentiation without loss of underlying identity. While originally observed in cosmological CMB analyses, the structure of the bias is generic and directly applicable to phase-sensitive computational systems, including superconducting and quantum-adjacent architectures. Importantly, this work does not propose new physics or alternative cosmological parameters. Instead, it identifies a reproducible analysis-level artifact that can mislead correlation-based diagnostics if boundary conditions are not explicitly modeled. This repository is intended to serve as: a bug report–style reference for boundary-induced phase bias, a citation anchor for discussions of reproducibility and hidden assumptions in phase-based analyses, and a cross-domain reference connecting cosmology, signal processing, and quantum-relevant computation. A browser-based supplementary tool is provided separately to enable independent verification and reuse of the proposed correction framework. Researchers encountering unexplained phase decoherence, mode divergence, or instability across projection layers are encouraged to cite this work as a canonical reference for boundary-induced systematic bias.