diff --git a/vllm/v1/attention/backends/mla/common.py b/vllm/v1/attention/backends/mla/common.py
index b09541dbf791..180625b6ce89 100755
--- a/vllm/v1/attention/backends/mla/common.py
+++ b/vllm/v1/attention/backends/mla/common.py
@@ -2061,7 +2061,7 @@ def forward(
                     attn_out,
                     lse,
                     get_dcp_group(),
-                    is_lse_base_on_e=not self._use_fi_prefill,
+                    is_lse_base_on_e=not getattr(self, "_use_fi_prefill", False),
                 )
 
             # v_up projection