diff --git a/crates/ml/src/trainers/dqn/trainer/training_loop.rs b/crates/ml/src/trainers/dqn/trainer/training_loop.rs
index 7327f415c..069145746 100644
--- a/crates/ml/src/trainers/dqn/trainer/training_loop.rs
+++ b/crates/ml/src/trainers/dqn/trainer/training_loop.rs
@@ -654,7 +654,29 @@ impl DQNTrainer {
                 }
             }
 
-            // G4: Gamma annealing — adaptive horizon based on atom utilization
+            // G4: Gamma annealing — adaptive horizon based on atom utilization.
+            //
+            // Prior direction (pre-2026-04-24 val-Flat-collapse fix #4):
+            //   util > 0.6 → γ += 0.005  (extend horizon when healthy)
+            //   util < 0.4 → γ -= 0.010  (shorten horizon when collapsed)
+            //
+            // That second arm creates a positive-feedback loop: atom
+            // collapse (low util) → lower γ → `γ × delta_z` shrinks →
+            // TD targets concentrate on fewer bins → deeper collapse.
+            // Observed on train-bv2n5: atom util stuck at 1% for 16
+            // epochs while this controller quietly nudged γ toward its
+            // 0.90 floor, reinforcing the symptom it was meant to
+            // mitigate. Per research-agent audit (2026-04-24).
+            //
+            // New direction: when atoms are collapsed, RAISE γ so
+            // `γ × atom_support` spans a larger fraction of the grid,
+            // spreading TD targets across more bins and breaking the
+            // loop. Slower step (0.005) than the healthy-branch to
+            // avoid overshoot.
+            //
+            // Clamps retained: [0.90, 0.95] at this layer; the fused
+            // trainer re-clamps to [0.90, 0.995] after its regime
+            // adjustment.
             {
                 let util = self.fused_ctx.as_ref()
                     .map(|f| f.utilization_ema())
@@ -662,7 +684,9 @@ impl DQNTrainer {
                 if util > 0.6 {
                     self.adaptive_gamma = (self.adaptive_gamma + 0.005).min(0.95);
                 } else if util < 0.4 {
-                    self.adaptive_gamma = (self.adaptive_gamma - 0.01).max(0.90);
+                    // Direction flipped (atom-collapse fix): RAISE γ to
+                    // widen the TD-target spread across the atom grid.
+                    self.adaptive_gamma = (self.adaptive_gamma + 0.005).min(0.95);
                 }
                 // C4/P4: Wire adaptive gamma into GPU trainer with temporal-coupled adjustment.
                 // apply_adaptive_gamma reads health+regime from ISV, adjusts, clamps [0.9, 0.995],