diff --git a/docs/docs/references/environment_variables.mdx b/docs/docs/references/environment_variables.mdx
index c00648b87..84e05966c 100644
--- a/docs/docs/references/environment_variables.mdx
+++ b/docs/docs/references/environment_variables.mdx
@@ -816,8 +816,8 @@ SGLang supports various environment variables that can be used to configure its
     </tr>
     <tr>
       <td style={{padding: "9px 12px", fontWeight: 500, backgroundColor: "rgba(255,255,255,0.02)"}}><code>SGLANG_FLASHINFER_MOE_FUSED_FINALIZE</code></td>
-      <td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.05)"}}>Use FlashInfer's fused atomic CUTLASS and CuTe DSL MoE finalize for best performance. Deterministic inference overrides this to <code>false</code>.</td>
-      <td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.02)"}}><code>true</code></td>
+      <td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.05)"}}>Use FlashInfer's fused atomic CUTLASS and CuTe DSL MoE finalize. Disabled by default for better numerical accuracy. Set to <code>1</code> to opt in for more aggressive performance. Deterministic inference overrides this to <code>false</code>.</td>
+      <td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.02)"}}><code>false</code></td>
     </tr>
     <tr>
       <td style={{padding: "9px 12px", fontWeight: 500, backgroundColor: "rgba(255,255,255,0.02)"}}><code>FLASHINFER_NVFP4_4OVER6</code></td>
diff --git a/python/sglang/srt/environ.py b/python/sglang/srt/environ.py
index a84f362fa..43cfca0a4 100644
--- a/python/sglang/srt/environ.py
+++ b/python/sglang/srt/environ.py
@@ -1044,7 +1044,7 @@ class Envs:
     # token count.
     SGLANG_TRTLLM_MOE_PDL_MAX_TOKENS = EnvInt(8192)
     # Use FlashInfer's fused atomic CUTLASS/CuTe DSL MoE finalize.
-    SGLANG_FLASHINFER_MOE_FUSED_FINALIZE = EnvBool(True)
+    SGLANG_FLASHINFER_MOE_FUSED_FINALIZE = EnvBool(False)
     # Master switch for the experimental TRT-LLM LoRA fast path; when OFF (default) every
     # fine-grained opt switch reads False, keeping non-experimental paths byte-identical.
     SGLANG_EXPERIMENTAL_LORA_OPTI = EnvBool(False)