diff --git a/crates/ml/src/cuda_pipeline/experience_kernels.cu b/crates/ml/src/cuda_pipeline/experience_kernels.cu
index 97a645b99..65fc38a2e 100644
--- a/crates/ml/src/cuda_pipeline/experience_kernels.cu
+++ b/crates/ml/src/cuda_pipeline/experience_kernels.cu
@@ -2785,7 +2785,18 @@ extern "C" __global__ void experience_env_step(
          * `exiting_trade=1` upstream (line ~2371), so this branch fires
          * for both — the segregation matters only for component attribution. */
         float base_reward = 2.0f * vol_normalized_return;
-        float capped_pnl = fminf(base_reward, 10.0f);
+        /* SP11 fix (2026-05-04): symmetric cap. The previous unilateral
+         * `fminf(base_reward, 10.0f)` capped profits at +10 but left losses
+         * unbounded — vol_normalized_return has no lower bound, so a single
+         * large adverse segment_return propagated as a large negative reward
+         * straight through the modifier chain into reward_components[+0],
+         * inflating PopArt input EMA (slot 63) and breaking C51/IQN/Bellman
+         * Q-target normalization. Empirical fingerprint from
+         * smoke-test-k9drh @ 774d7552a: ep1 r_popart min=-9186, ep2
+         * min=-79089 (growing), max stuck at +10. Spec semantic is bilateral
+         * [-10, +10]; enforce bilaterally per pearl_bounded_modifier_outputs_
+         * require_structural_activation. */
+        float capped_pnl = fmaxf(-10.0f, fminf(base_reward, 10.0f));
         if (trail_triggered) {
             r_trail = capped_pnl;
         } else {
diff --git a/docs/dqn-wire-up-audit.md b/docs/dqn-wire-up-audit.md
index 3085a6c36..a1107a5d1 100644
--- a/docs/dqn-wire-up-audit.md
+++ b/docs/dqn-wire-up-audit.md
@@ -5585,7 +5585,11 @@ Sharpe degrades within fold despite the SP11 controller working
 correctly.
 
 All known multiplicative modifiers are structurally bounded:
-- `r_popart = capped_pnl ≤ 10` (experience_kernels.cu:2744)
+- `r_popart = capped_pnl ∈ [-10, +10]` (experience_kernels.cu:2799,
+  bilateral as of the SP11 symmetric-cap fix — see "Resolution
+  (2026-05-04)" below). Pre-fix: `fminf(base_reward, 10.0f)` at
+  line 2788 only capped the upper tail; losses were unbounded —
+  that WAS the inflater this diagnostic was searching for.
 - `× conviction ∈ (0, 1)` via sigmoid at experience_kernels.cu:7579
 - `× cf_flip ∈ {-1, +1}`
 - `× shaping_scale ∈ [0, 1]`
@@ -5597,6 +5601,58 @@ inflater, this commit adds GPU-side instrumentation (data-gathering
 only, no fix) capturing the running `reward` cascade variable + per-
 component locals at every checkpoint.
 
+### Resolution (2026-05-04)
+
+The diagnostic instrumentation in `smoke-test-k9drh @ 774d7552a`
+captured the asymmetry directly: `ep1 r_popart min=-9186, max=+10`
+and `ep2 min=-79089, max=+10` (max stuck, min growing each epoch).
+Root cause: line 2788 `float capped_pnl = fminf(base_reward, 10.0f)`
+— unilateral upper cap; `base_reward = 2.0f * vol_normalized_return`
+where `vol_normalized_return = segment_return / vol_norm` has no
+structural lower bound (signed P&L). A single large adverse
+`segment_return` produced an arbitrarily negative `capped_pnl` →
+`r_popart` → `r_weighted` → `reward_components[+0]` → slot 63
+(PopArt input EMA), inflating C51/IQN/Bellman normalization scale
+and breaking Q-target consistency across epochs.
+
+Fix:
+```c
+float capped_pnl = fmaxf(-10.0f, fminf(base_reward, 10.0f));
+```
+Spec semantic was always bilateral `[-10, +10]`; the implementation
+was unilateral. Per
+`pearl_bounded_modifier_outputs_require_structural_activation`:
+spec-bounded values require BILATERAL structural enforcement.
+
+Audit follow-through (per `feedback_no_partial_refactor`): all
+other `fminf(.,K)` and `fmaxf(.,K)` clamps in
+`experience_kernels.cu` reviewed for the same asymmetric-clamp
+pattern. Findings:
+- Reward modifier chain (3260-3500): all bounded modifiers operate
+  on the post-cap `r_weighted`; once `capped_pnl` is bilateral, the
+  whole downstream chain is bounded.
+- Bilateral clamps verified correct at: 515-517 (cost bands),
+  2174/2191/2227 (conviction/Kelly), 3300 (stability),
+  3729/3763 (cf_reward), 3452 (capital-floor), 5076/5210/5213/
+  5461/5535 ([0,1] gates), 6353 (d_h0), 6693/6694 (ADX/CUSUM).
+- Intentional asymmetries verified at: 1078 (cosine_progress ≥ 0
+  structurally), 1082-1085 (eps×mult ≥ 0 structurally + EPS_FLOOR
+  at 1090-1094), 2564-2565 (max_dd lower-unbounded by drawdown
+  semantic), 2873/2949 (fabsf-based unit ≥ 0 structurally), 4574
+  (guarded by `if best_pnl > 0.0f`), 5896 (input-gate underflow
+  toward 0 is correct sigmoid-like semantic).
+- Latent finding flagged separately (NOT fixed in this commit —
+  feature-side, requires consumer audit): `plan_isv[PNL_VS_TARGET]`
+  at 850 and `plan_isv[PNL_VS_STOP]` at 853 are upper-clamped at
+  2.0 but lower-unbounded; mirrored in `backtest_plan_kernel.cu`.
+  These feed `assemble_state` (line 956) as policy features, not
+  reward components, so out of scope for this reward-chain fix.
+
+Diagnostic instrumentation (commit 774d7552a) NOT removed in this
+commit — kept for the symmetric-cap validation smoke on L40S.
+Removal lands in the follow-up commit after smoke validates the
+fix end-to-end.
+
 ### What it adds
 
 | Component | Detail |