diff --git a/modelopt/onnx/autocast/graphsanitizer.py b/modelopt/onnx/autocast/graphsanitizer.py
index 85f407a59..97c987f36 100644
--- a/modelopt/onnx/autocast/graphsanitizer.py
+++ b/modelopt/onnx/autocast/graphsanitizer.py
@@ -331,6 +331,7 @@ def _match_layernorm_pattern(self, mean_node: onnx.NodeProto) -> dict | None:
             # Find and extract scale and bias nodes if present
             scale = None
             bias = None
+            scale_dimension = None
             final_node = div_node
             nodes_to_remove = [
                 mean_node,
diff --git a/modelopt/onnx/autocast/nodeclassifier.py b/modelopt/onnx/autocast/nodeclassifier.py
index 0a7638429..828f522e2 100644
--- a/modelopt/onnx/autocast/nodeclassifier.py
+++ b/modelopt/onnx/autocast/nodeclassifier.py
@@ -286,6 +286,11 @@ def _check_inner(self, node):
             axis_array = onnx.numpy_helper.to_array(axis_init)
             assert axis_array.ndim == 0 or (axis_array.ndim == 1 and axis_array.size == 1)
             axis = int(axis_array.item())
+            # Normalize negative axis and check bounds
+            if axis < 0:
+                axis = len(input_0_dims) + axis
+            if axis < 0 or axis >= len(input_0_dims):
+                return False
             if input_0_dims[axis] > self.max_depth_of_reduction:
                 self.reduction_depth = input_0_dims[axis]
 
@@ -449,18 +454,22 @@ def run(self, ref_outputs_dict=None):
         """
         exclude_node_rules = self._gen_exclude_node_rules(ref_outputs_dict)
         include_node_rules = self._gen_include_node_rules()
-        low_precision_nodes = self.custom_ops_low_precision_nodes or []
+        # Use a set to avoid duplicates
+        low_precision_nodes_set = set(self.custom_ops_low_precision_nodes or [])
         high_precision_nodes = []
         for node in self.model.graph.node:
+            # Skip if already classified as low precision
+            if node.name in low_precision_nodes_set:
+                continue
             # If any condition is met - node will be executed in high precision
-            if (
-                node.name not in low_precision_nodes
-                and any(rule.check(node) for rule in exclude_node_rules)
-                and not any(rule.check(node) for rule in include_node_rules)
+            if any(rule.check(node) for rule in exclude_node_rules) and not any(
+                rule.check(node) for rule in include_node_rules
             ):
                 high_precision_nodes.append(node.name)
             else:
-                low_precision_nodes.append(node.name)
+                low_precision_nodes_set.add(node.name)
+        # Convert back to list for return value
+        low_precision_nodes = list(low_precision_nodes_set)
         logger.debug(f"Low Precision Nodes: {low_precision_nodes}")
         logger.debug(f"High Precision Nodes: {high_precision_nodes}")
         return low_precision_nodes, high_precision_nodes