diff --git a/flashinfer/fused_moe/core.py b/flashinfer/fused_moe/core.py
index 80a464f51d..847ce7b444 100644
--- a/flashinfer/fused_moe/core.py
+++ b/flashinfer/fused_moe/core.py
@@ -1236,6 +1236,7 @@ def forward(
                     output,
                     [-1, -1] if tactic == -1 else tactic,
                     kwargs.get("norm_topk_prob", True),
+                    kwargs.get("routing_replay_out"),
                 )
             else:
                 moe_op.trtllm_fp4_block_scale_moe(
@@ -1272,6 +1273,7 @@ def forward(
                     output,
                     [-1, -1] if tactic == -1 else tactic,
                     kwargs.get("norm_topk_prob", True),
+                    kwargs.get("routing_replay_out"),
                 )
 
     @register_custom_op(
diff --git a/include/flashinfer/trtllm/fused_moe/RoutingKernel.h b/include/flashinfer/trtllm/fused_moe/RoutingKernel.h
index 0ebab0143d..e16ee6600f 100644
--- a/include/flashinfer/trtllm/fused_moe/RoutingKernel.h
+++ b/include/flashinfer/trtllm/fused_moe/RoutingKernel.h
@@ -69,11 +69,6 @@ struct DataBase {
   // Together with mPtrTopKWeights, they form the top-k experts for each token
   int32_t* mPtrTopKIds{nullptr};
 
-  // optional: if nullptr, no routing replay recording occurs
-  // dim: [mNumTokens, mTopK]
-  // Records the selected expert IDs per token for replay
-  int16_t* mPtrRoutingReplayOut{nullptr};
-
   // optional: if `nullptr`, scores are used directly as input.
   // If it is given, it must represent a packed value s.t. the most significant
   // 16/32 bits represent the score without sigmoid activation and
@@ -108,6 +103,12 @@ struct DataBase {
   int32_t mLocalExpertsStartIdx;
   int32_t mLocalExpertsStrideLog2;
   int32_t mNumLocalExperts;
+
+  // optional: if nullptr, no routing replay recording occurs
+  // dim: [mNumTokens, mTopK]
+  // Records the selected expert IDs per token for replay
+  // NOTE: placed at end of struct to preserve field offsets for existing routing kernels
+  int16_t* mPtrRoutingReplayOut{nullptr};
 };
 
 template <typename InputT_, typename OutputT_, int MaxNumExperts_, int MaxNumTopExperts_>
@@ -132,7 +133,6 @@ struct KernelParamsBase {
   OutputT* mPtrTopKWeights = nullptr;
   int32_t* mPtrTopKIds = nullptr;
   InputT const* mPtrScores = nullptr;
-  int16_t* mPtrRoutingReplayOut = nullptr;
 
   // Public scalar members
   int32_t mNumTokens = 0;
@@ -144,6 +144,9 @@ struct KernelParamsBase {
   int32_t mLocalExpertsStrideLog2 = 0;
   int32_t mNumLocalExperts = 0;
 
+  // NOTE: placed at end to preserve field offsets for existing routing kernels
+  int16_t* mPtrRoutingReplayOut = nullptr;
+
   // Public initialization function - make it a template to accept different Data types
   template <typename DataType>
   void setBaseParams(DataType const& data) {