diff --git a/python/sglang/srt/speculative/eagle_worker.py b/python/sglang/srt/speculative/eagle_worker.py
index 6e1a41249..b6c53422e 100644
--- a/python/sglang/srt/speculative/eagle_worker.py
+++ b/python/sglang/srt/speculative/eagle_worker.py
@@ -796,6 +796,11 @@ class EAGLEWorker(TpModelWorker):
         spec_info: EagleVerifyInput,
         seq_lens_pre_verify: torch.Tensor,
     ):
+        # Under DP attention, some ranks can be IDLE during target verify and never
+        # initialize mamba forward metadata for this step.
+        if batch.forward_mode.is_idle():
+            return
+
         accepted_length = (
             torch.tensor(
                 res.accept_length_per_req_cpu,