diff --git a/crates/ml-backtesting/cuda/resting_orders.cu b/crates/ml-backtesting/cuda/resting_orders.cu
index dcc39fccf..94c2bee9f 100644
--- a/crates/ml-backtesting/cuda/resting_orders.cu
+++ b/crates/ml-backtesting/cuda/resting_orders.cu
@@ -336,29 +336,41 @@ extern "C" __global__ void resting_orders_step(
                 if (s.queue_position >= trade_abs) {
                     s.queue_position -= trade_abs;
                 } else {
-                    const float over = trade_abs - s.queue_position;
-                    s.queue_position = 0.0f;
-                    const float take = (over < s.size_remaining) ? over : s.size_remaining;
-                    if (take > 0.0f) {
-                        // Filled `take` lots at our limit price (queue position reached us).
-                        const float cost = take * s.price;
-                        apply_fill_to_pos(pos, take, cost, s.side,
-                                          b, cost_per_lot_per_side_per_b, total_fees_per_b,
-                                          nan_avg_px, nan_realised, nan_realized_pnl,
-                                          vwap_zero_open_flat, vwap_huge_open_flat,
-                                          vwap_zero_scale_in,  vwap_huge_scale_in,
-                                          vwap_zero_flip,      vwap_huge_flip,
-                                          last_bad_vwap,       last_bad_path);
-                        s.size_remaining -= take;
-                        emit_audit(audit_base, audit_head, b, (unsigned int)ring_cap_events,
-                                   current_ts_ns,
-                                   pack_slot_tag(0 /*SlotKind::Limit*/, (unsigned char)i, s.gen_counter),
-                                   1 /*SubmitLimit*/, s.side, (unsigned short)take,
-                                   (int)(s.price / tick_size + 0.5f), 0);
-                        if (s.size_remaining <= 0.0f) {
-                            cancel_oco_pair(orders, s.oco_pair);
-                            s.active = 0;
-                            continue;
+                    // Sentinel-priced (market-like) orders use s.price = 1e9 (buy)
+                    // or 0 (sell) so the marketability check below always crosses.
+                    // The queue-decay arm MUST NOT use s.price for cost because it
+                    // would inject the sentinel into avg_px (S1.23 root cause:
+                    // zero_flat=194, huge_flat=216). Absorb the queue depletion
+                    // only; the marketability check fires this same iteration via
+                    // walk_* with book-derived prices.
+                    const bool is_sentinel_price = (s.price < min_px) || (s.price > max_px);
+                    if (is_sentinel_price) {
+                        s.queue_position = 0.0f;
+                    } else {
+                        const float over = trade_abs - s.queue_position;
+                        s.queue_position = 0.0f;
+                        const float take = (over < s.size_remaining) ? over : s.size_remaining;
+                        if (take > 0.0f) {
+                            // Filled `take` lots at our limit price (queue position reached us).
+                            const float cost = take * s.price;
+                            apply_fill_to_pos(pos, take, cost, s.side,
+                                              b, cost_per_lot_per_side_per_b, total_fees_per_b,
+                                              nan_avg_px, nan_realised, nan_realized_pnl,
+                                              vwap_zero_open_flat, vwap_huge_open_flat,
+                                              vwap_zero_scale_in,  vwap_huge_scale_in,
+                                              vwap_zero_flip,      vwap_huge_flip,
+                                              last_bad_vwap,       last_bad_path);
+                            s.size_remaining -= take;
+                            emit_audit(audit_base, audit_head, b, (unsigned int)ring_cap_events,
+                                       current_ts_ns,
+                                       pack_slot_tag(0 /*SlotKind::Limit*/, (unsigned char)i, s.gen_counter),
+                                       1 /*SubmitLimit*/, s.side, (unsigned short)take,
+                                       (int)(s.price / tick_size + 0.5f), 0);
+                            if (s.size_remaining <= 0.0f) {
+                                cancel_oco_pair(orders, s.oco_pair);
+                                s.active = 0;
+                                continue;
+                            }
                         }
                     }
                 }