diff --git a/python/sglang/srt/server_args.py b/python/sglang/srt/server_args.py
index 3a8653d7c..ea01528c9 100644
--- a/python/sglang/srt/server_args.py
+++ b/python/sglang/srt/server_args.py
@@ -5442,6 +5442,8 @@ class ServerArgs:
                 envs.SGLANG_OPT_FP8_WO_A_GEMM.set(False)
                 envs.SGLANG_OPT_USE_TOPK_V2.set(False)
                 envs.SGLANG_OPT_USE_TILELANG_MHC_PRE.set(False)
+                if not envs.SGLANG_OPT_FUSE_MHC_POST_PRE.is_set():
+                    envs.SGLANG_OPT_FUSE_MHC_POST_PRE.set(True)
                 envs.SGLANG_OPT_DEEPGEMM_HC_PRENORM.set(False)
                 envs.SGLANG_FP8_PAGED_MQA_LOGITS_TORCH.set(True)
                 # Prefer TileLang over the Torch fallback.