diff --git a/arborist/qa/relevance/manifest.json b/arborist/qa/relevance/manifest.json
index 41b180a..83532b3 100644
--- a/arborist/qa/relevance/manifest.json
+++ b/arborist/qa/relevance/manifest.json
@@ -15,7 +15,8 @@
     "as_runtime_demotion_veto": "NOT VIABLE on this design (§3.2.2 step 2 measurement)",
     "as_advisory_soft_signal": "viable — surface the raw score on the render tail or as bench telemetry; no threshold needed",
     "as_multi_signal_factor": "viable — combine with title-relevance, deflection, coherence sidecars for a weighted advisory",
-    "as_contrastive_signal": "viable and worth measuring — relative score (Q→A vs claim→source, or within an answer's claims) may discriminate where absolute threshold does not"
+    "as_contrastive_signal": "TESTED 2026-05-13 — DOES NOT SEPARATE on real bench-qa data: 97% of STRICT-fires at cb-θ have BOTH Q→A and A→ctx_lead low (co-varying); only 3% match the 'high A→ctx, low Q→A' deflection signature. The A→ctx axis isn't measuring what was hoped — a focused-claim against a 30KB topic-broad context scores low by default (that's the normal STRICT shape), so the delta doesn't discriminate. Contrastive rescue path is closed.",
+    "preprocessing_cleaning_is_free_improvement": "claim-lattice metadata [E\\d+ | … | hash: '…'] depresses scores by ~3-6 pts on cleaned vs raw; clean_for_relevance is baked into check_* by default. Universal win across all 6 swept models (-0.5 to -5.6 pts FP)."
   },
   "alternates": [
     {"relevance_model_version": "relevance-shadow-v1-bge-reranker-large", "hf_repo": "BAAI/bge-reranker-large", "license": "MIT", "approx_mb": 560, "note": "LARGE end of the spectrum — added §3.2.1 round-2 (does bigger BGE beat bge-base?)"},