diff --git a/app/assets/services/path_utils.py b/app/assets/services/path_utils.py
index c13b86a45..7c27c8878 100644
--- a/app/assets/services/path_utils.py
+++ b/app/assets/services/path_utils.py
@@ -209,8 +209,14 @@ def get_asset_category_and_relative_path(
         return "temp", _compute_relative(fp_abs, temp_base)
 
     # 4) models (check deepest matching base to avoid ambiguity)
+    ext = os.path.splitext(fp_abs)[1].lower()
     best: tuple[int, str, str] | None = None  # (base_len, bucket, rel_inside_bucket)
-    for bucket, bases, _exts in get_comfy_models_folders():
+    for bucket, bases, extensions in get_comfy_models_folders():
+        # A bucket only lists files within its extension set (empty set
+        # accepts any extension), so a bucket that cannot load the file
+        # must not contribute a loader path.
+        if extensions and ext not in extensions:
+            continue
         for b in bases:
             base_abs = os.path.abspath(b)
             if not _check_is_within(fp_abs, base_abs):
diff --git a/tests-unit/assets_test/services/test_path_utils.py b/tests-unit/assets_test/services/test_path_utils.py
index ad769d209..ddf23c676 100644
--- a/tests-unit/assets_test/services/test_path_utils.py
+++ b/tests-unit/assets_test/services/test_path_utils.py
@@ -523,6 +523,42 @@ class TestLoaderPath:
         assert compute_logical_path(str(f)) == "models/not_registered/orphan.bin"
         assert compute_loader_path(str(f)) is None
 
+    def test_extension_mismatch_in_registered_bucket_has_no_loader_path(self, fake_dirs):
+        # Inside a registered bucket, but the bucket's extension set cannot
+        # load it: no model_type tag, and no loader path either.
+        f = fake_dirs["models"] / "notes.txt"
+        f.touch()
+
+        assert compute_logical_path(str(f)) == "models/checkpoints/notes.txt"
+        assert compute_loader_path(str(f)) is None
+
+    def test_shared_base_loader_path_uses_extension_matching_bucket(self, fake_dirs):
+        shared_root = fake_dirs["models"].parent / "unet"
+        shared_root.mkdir()
+        f = shared_root / "wan.gguf"
+        f.touch()
+
+        with patch(
+            "app.assets.services.path_utils.get_comfy_models_folders",
+            return_value=[
+                ("diffusion_models", [str(shared_root)], {".safetensors"}),
+                ("unet_gguf", [str(shared_root)], {".gguf"}),
+            ],
+        ):
+            assert compute_loader_path(str(f)) == "wan.gguf"
+
+    def test_match_all_bucket_provides_loader_path_for_any_extension(self, fake_dirs):
+        custom_root = fake_dirs["models"].parent / "custom_bucket"
+        custom_root.mkdir()
+        f = custom_root / "weights.bin"
+        f.touch()
+
+        with patch(
+            "app.assets.services.path_utils.get_comfy_models_folders",
+            return_value=[("custom_bucket", [str(custom_root)], set())],
+        ):
+            assert compute_loader_path(str(f)) == "weights.bin"
+
     def test_extra_path_model_has_loader_path_but_no_logical_path(self, tmp_path: Path):
         """Registered category base outside models_dir (extra_model_paths style).