What we tested
Eight exp-csi-static runs (sweep 01KT9BPF4V470GJSQQAG1XE67F, all attached, all gate_passed) on the through-wall rig (resplan-12439-floor-0 / csi-link-resplan-12439-multiroom, 24 placements, depth 3, seed 0): arm ∈ {as-stored palette, scene_overrides.uniform_material: concrete} × band {2.4, 5.0 GHz} × occupancy {0, 6}. The runner's 2026-06-04 extensions carried the arm switch (scene_overrides) and the second-order statistic (delay_spread_ns from the CFR power-delay profile). Two-sample KS tests were computed per (band, occupancy) on per-placement mean_amp_db and delay_spread_ns, pooled and per link (table: material_ks.csv in the session scratch dir).
Discovered while authoring the brief: the staged palette is already uniform drywall on every current floor — the import does not tag per-wall materials. The original heterogeneous-vs-uniform framing was therefore counterfactual; this session tests palette sensitivity (drywall → concrete, a large but realistic worst-case perturbation: ε_r 2.94 → 5.31 plus conductivity).
What we found
Criterion 1 — both arms staged and ran cleanly, 8/8 runs with links.parquet incl. delay_spread_ns, no NaN/Inf. Criterion 2 — the KS table is decisive on every cell: pooled first-order KS-D = 0.74–1.00 (mean_amp_db) and pooled second-order KS-D = 0.27–0.60 (delay_spread_ns), all p < 4e-4; per-link maxima reach 1.00. Criterion 3 — the decision rule fires on its strongest branch (KS-D ≥ 0.15 on first and second order): the wall-material palette is load-bearing for both blockage and multipath statistics.
What it means for the thesis chain
Every prior default-material CSI result is conditional on the drywall tag being correct: the sealed sessions c-csi-crowd-temporal/01KT99FX2Z3RG2W2DZ4FVCVTH7 and c-csi-cross-geometry-resplan/01KT98WKH2HYQYP4EP79G09CEG (and the unsealed occlusion/body-EM corpora) all ran on the untagged uniform-drywall default. Because the perturbation tested here is a full palette swap, this session quantifies sensitivity to the palette, not the error of plausible mis-tagging — drywall is the plausible tag for ResPlan interior partitions, so those results are not invalidated, but their fidelity now rests on an unverified import-side assumption. Escalation per the brief: (1) per-wall material tagging at import becomes a real requirement, not nice-to-have; (2) the furniture-scatterer extension (obstacle cells → extruded meshes) rises in priority since material fidelity demonstrably moves second-order statistics; (3) exp-csi-calibration against real hardware remains the only way to fix the absolute palette. Cross-geometry caveat: the ×3.8–×7.7 LOFO drift was measured with the SAME palette on all six floors, so palette uncertainty does not confound the relative drift result — it bounds absolute magnitudes only.