tau-MnAl L10 calibration screening chain false-negative anchors

4-gate screening sweep on Apollo tau-MnAl calibration CIF: moment, Curie T, e_hull, MAE. Screening chain returns REJECT on a known RE-free hard magnet, with documented model biases that exceed prior worst-case bounds (NEMAD Curie T: -423 K vs prior -100 to -300 K range; ALIGNN e_hull: 2.39 eV/atom vs prior 0.45-1.6 eV/atom; tb2j MAE: 15x underprediction vs prior 20-40%). Easy axis direction correctly predicted (001 c-axis), qualifying MAE route as a uniaxial-anisotropy filter but not a quantitative K1 predictor for L10 intermetallics. Conclusion: systematic bias correction is mandatory before the chain can evaluate new RE-free magnet candidates.