diff --git a/studio/backend/core/inference/diffusion_transformer_quant.py b/studio/backend/core/inference/diffusion_transformer_quant.py
index 173d0aaa86..fcaf66f6d3 100644
--- a/studio/backend/core/inference/diffusion_transformer_quant.py
+++ b/studio/backend/core/inference/diffusion_transformer_quant.py
@@ -324,7 +324,7 @@ def make_filter_fn(min_features: int, exclude_name_tokens: tuple[str, ...] = ())
         if in_features < min_features or out_features < min_features:
             return False
         if exclude_name_tokens:
-            name = fqn.lower()
+            name = fqn.lower() if fqn else ""
             if any(tok in name for tok in exclude_name_tokens):
                 return False
         return True
diff --git a/studio/backend/tests/test_diffusion_transformer_quant.py b/studio/backend/tests/test_diffusion_transformer_quant.py
index 9ee0af7649..8f6ef6594d 100644
--- a/studio/backend/tests/test_diffusion_transformer_quant.py
+++ b/studio/backend/tests/test_diffusion_transformer_quant.py
@@ -351,6 +351,10 @@ def test_make_filter_fn_int8_excludes_modulation_and_embedders(monkeypatch):
         assert keep(big(), fqn) is True, fqn
     # Without the exclusion (fp8 path), the modulation layer is kept.
     assert make_filter_fn(512)(big(), "transformer_blocks.0.norm1.linear") is True
+    # A None / empty fqn must not crash the exclusion check (defensive against the callback
+    # passing no name); with no name nothing matches the exclusion tokens -> kept.
+    assert keep(big(), None) is True
+    assert keep(big(), "") is True
 
 
 # ── apply ───────────────────────────────────────────────────────────────────────