Treat store_kv=None as use config default (upstream forwards thread None through)

modeling_sdar.py

@@ -264,7 +264,11 @@ class SDARAttention(nn.Module):
         # I-DLM / strict-causal mode (`config.use_regular_causal=True`) uses the standard HF cache
         # convention: every cached forward commits its KVs. In SDAR block-diffusion mode, callers pass
         # `store_kv=True` for commit forwards and `store_kv=False` for retrieve-only denoising passes.
-        store_kv = kwargs.get("store_kv", bool(getattr(self.config, "use_regular_causal", False)))
+        # Upstream forwards thread `store_kv: Optional[bool] = None` through, so a missing caller kwarg
+        # still arrives here as `None` — treat that as "use config default" rather than False.
+        store_kv = kwargs.get("store_kv", None)
+        if store_kv is None:
+            store_kv = bool(getattr(self.config, "use_regular_causal", False))
         if past_key_value is not None and store_kv:
             # Store new kv into the cache (and get concatenated result).
             key_states, value_states = past_key_value.update(