diff --git a/python/sglang/srt/layers/attention/trtllm_mla_backend.py b/python/sglang/srt/layers/attention/trtllm_mla_backend.py
index e5489ce7a..b74124da2 100755
--- a/python/sglang/srt/layers/attention/trtllm_mla_backend.py
+++ b/python/sglang/srt/layers/attention/trtllm_mla_backend.py
@@ -616,6 +616,13 @@ class TRTLLMMLABackend(FlashInferMLAAttnBackend):
         ):
             bs = forward_batch.batch_size
             self.forward_decode_metadata = TRTLLMMLADecodeMetadata()
+            # This is necessary because the backend instance persists across forward passes,
+            # and forward_prefill_metadata from a previous regular extend call could still be set.
+            if (
+                forward_batch.forward_mode.is_target_verify()
+                or forward_batch.forward_mode.is_draft_extend(include_v2=True)
+            ):
+                self.forward_prefill_metadata = None
             # Get maximum sequence length.
             if getattr(forward_batch, "seq_lens_cpu", None) is not None:
                 max_seq = forward_batch.seq_lens_cpu.max().item()