diff --git a/tests/test_generate_popular_node_signatures.py b/tests/test_generate_popular_node_signatures.py
index c47b183..75c8d01 100644
--- a/tests/test_generate_popular_node_signatures.py
+++ b/tests/test_generate_popular_node_signatures.py
@@ -260,6 +260,49 @@ NODE_CLASS_MAPPINGS = {
         self.assertEqual({}, result["nodes"])
         self.assertEqual("no_static_nodes", result["pack"]["status"])
 
+    def test_duplicate_node_id_with_unsupported_mapping_value_skips_static_node(self):
+        source_a = '''
+class StaticDupNode:
+    RETURN_TYPES = ("IMAGE",)
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "image": ("IMAGE",),
+            },
+        }
+
+
+NODE_CLASS_MAPPINGS = {
+    "DupNode": StaticDupNode,
+}
+'''
+        source_b = '''
+def build_node():
+    return object()
+
+
+NODE_CLASS_MAPPINGS = {
+    "DupNode": build_node(),
+}
+'''
+        with tempfile.TemporaryDirectory() as tmp:
+            Path(tmp, "a.py").write_text(textwrap.dedent(source_a), encoding="utf-8")
+            Path(tmp, "b.py").write_text(textwrap.dedent(source_b), encoding="utf-8")
+            result = extract_repo_signatures(
+                Path(tmp),
+                {
+                    "id": "unsupported-duplicate-node-pack",
+                    "title": "Unsupported Duplicate Node Pack",
+                    "repository": "https://github.com/example/unsupported-duplicate-node-pack",
+                    "rank": 1,
+                },
+            )
+
+        self.assertEqual({}, result["nodes"])
+        self.assertEqual("no_static_nodes", result["pack"]["status"])
+
     def test_unsupported_reassignment_invalidates_static_env_value(self):
         source = '''
 def build_inputs():
@@ -767,6 +810,33 @@ NODE_CLASS_MAPPINGS = {
         self.assertEqual({}, result["nodes"])
         self.assertEqual("no_static_nodes", result["pack"]["status"])
 
+    def test_arbitrary_call_observing_mutable_env_value_invalidates_static_env_value(self):
+        source = '''
+INPUTS = {
+    "required": {
+        "image": ("IMAGE",),
+    },
+}
+observe(INPUTS)
+
+
+class ObservedInputEnvNode:
+    RETURN_TYPES = ("IMAGE",)
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return INPUTS
+
+
+NODE_CLASS_MAPPINGS = {
+    "ObservedInputEnvNode": ObservedInputEnvNode,
+}
+'''
+        result = self._extract_source(source, "observed-input-env-pack")
+
+        self.assertEqual({}, result["nodes"])
+        self.assertEqual("no_static_nodes", result["pack"]["status"])
+
     def test_function_default_mutation_invalidates_static_env_value(self):
         source = '''
 INPUTS = {
@@ -1685,6 +1755,30 @@ NODE_CLASS_MAPPINGS = {
         self.assertEqual({}, result["nodes"])
         self.assertEqual("no_static_nodes", result["pack"]["status"])
 
+    def test_return_types_used_as_callee_skips_node(self):
+        source = '''
+class CalleeObservedReturnTypesNode:
+    RETURN_TYPES = ["IMAGE"]
+    RETURN_TYPES()
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "image": ("IMAGE",),
+            },
+        }
+
+
+NODE_CLASS_MAPPINGS = {
+    "CalleeObservedReturnTypesNode": CalleeObservedReturnTypesNode,
+}
+'''
+        result = self._extract_source(source, "callee-observed-return-types-pack")
+
+        self.assertEqual({}, result["nodes"])
+        self.assertEqual("no_static_nodes", result["pack"]["status"])
+
     def test_return_types_function_default_arbitrary_call_skips_node(self):
         source = '''
 class DefaultArbitraryCallReturnTypesNode:
@@ -3735,6 +3829,31 @@ NODE_CLASS_MAPPINGS = {
         self.assertEqual({}, result["nodes"])
         self.assertEqual("no_static_nodes", result["pack"]["status"])
 
+    def test_input_types_used_as_callee_skips_node(self):
+        source = '''
+class CalleeObservedInputTypesNode:
+    RETURN_TYPES = ("IMAGE",)
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "image": ("IMAGE",),
+            },
+        }
+
+    INPUT_TYPES()
+
+
+NODE_CLASS_MAPPINGS = {
+    "CalleeObservedInputTypesNode": CalleeObservedInputTypesNode,
+}
+'''
+        result = self._extract_source(source, "callee-observed-input-types-pack")
+
+        self.assertEqual({}, result["nodes"])
+        self.assertEqual("no_static_nodes", result["pack"]["status"])
+
     def test_input_types_alias_observed_by_arbitrary_call_skips_node(self):
         source = '''
 class AliasObservedInputTypesNode:
diff --git a/tools/generate_popular_node_signatures.py b/tools/generate_popular_node_signatures.py
index b485400..a781966 100644
--- a/tools/generate_popular_node_signatures.py
+++ b/tools/generate_popular_node_signatures.py
@@ -635,6 +635,7 @@ def _arbitrary_call_observed_names(stmt):
             self.visit(node.args)
 
         def visit_Call(self, node):
+            names.update(_referenced_names(node.func))
             if isinstance(node.func, ast.Attribute):
                 names.update(_referenced_names(node.func.value))
             for arg in node.args:
@@ -779,6 +780,10 @@ def _apply_module_stmt_to_env(stmt, env, class_bindings=None):
     else:
         _invalidate_class_bindings(class_bindings, names)
         _invalidate_env_names(env, names)
+    observed_names = _arbitrary_call_observed_names(stmt)
+    for name in observed_names:
+        if name in env and _is_mutable_static_value(env[name]):
+            _invalidate_env_name(env, name)
     if isinstance(stmt, ast.ClassDef):
         if class_bindings is not None:
             if _is_trivially_safe_class_def(stmt):
@@ -1782,6 +1787,19 @@ def _node_class_mappings(tree):
     return {node_type: binding for node_type, (_class_name, binding) in mappings.items() if node_type}
 
 
+def _node_class_mapping_keys(tree):
+    if _has_module_wildcard_import(tree):
+        return set()
+    mappings = _final_module_dict(
+        tree,
+        "NODE_CLASS_MAPPINGS",
+        lambda _value, _env, _class_bindings: True,
+    )
+    if not all(isinstance(node_type, str) for node_type in mappings):
+        return set()
+    return {node_type for node_type in mappings if node_type}
+
+
 def _display_mappings(tree):
     displays = _final_module_dict(
         tree,
@@ -1880,7 +1898,15 @@ def extract_repo_signatures(repo_dir, pack_meta):
             continue
         env = _collect_module_env(tree)
         mappings = _node_class_mappings(tree)
+        mapping_node_types = _node_class_mapping_keys(tree)
         displays = _display_mappings(tree)
+        for node_type in sorted(mapping_node_types):
+            prior_path = node_sources.get(node_type)
+            if prior_path is not None and prior_path != path:
+                duplicate_node_types.add(node_type)
+                nodes.pop(node_type, None)
+                continue
+            node_sources.setdefault(node_type, path)
         if displays is _INVALID:
             continue
         for node_type, binding in sorted(mappings.items()):