docs: explain mixed-traffic instability

1 files changed, 9 insertions, 0 deletions

diff --git a/MIXED_TRAFFIC.md b/MIXED_TRAFFIC.md
index 4852ef0..0412bd5 100644
--- a/MIXED_TRAFFIC.md
+++ b/MIXED_TRAFFIC.md
@@ -129,6 +129,15 @@ and cost invariants therefore pass, but they do not rescue the failed finite,
 accuracy, alignment, tracking, or norm checks. MT-2 and MT-3 remain untouched;
 the branch closes without changing traffic strength or predictor schedule.
 
+A post-failure training-only audit performs no validation or test evaluation
+and stops at the first training-active nonfinite tensor. The first failures are
+the stem forward weight and its momentum at task step 23 for raw, 69 for
+norm-matched raw, and 74 for innovation. The predictor slope and reciprocal
+feedback weights remain finite at those points. Norm matching and innovation
+therefore delay the same multiplicative local instability rather than remove
+it. `THEORY.md` derives the linearized residual-coupling term `D W C` and shows
+why residual RMS alone cannot certify stability.
+
 ## MT-2: frozen full validation gate
 
 Copy MT-1 exactly for 200 epochs. The three jobs remain seed 0 and do not touch