When I remove the Editor Curve through SerializeObject, the Application.Tick() hook up and occupies the main thread about two minutes. Why?

When I remove the Editor Curve through SerializeObject, the Application.Tick() hook up and occupies the main thread about two minutes.

Why this happen?

SerializedObject serializedObject = new SerializedObject(clip);
SerializedProperty serializedProperty = serializedObject.FindProperty("m_EditorCurves");
serializedProperty.ClearArray();
SerializedProperty serializedProperty1 = serializedObject.FindProperty("m_RotationCurves");
if (serializedProperty1.arraySize > 0)
{
      SerializedProperty serializedProperty2 = serializedObject.FindProperty("m_EulerEditorCurves");
      serializedProperty2.ClearArray();
}
serializedObject.ApplyModifiedProperties();
serializedObject.Update();
EditorUtility.SetDirty(animationClip);
AssetDatabase.SaveAssets();
AssetDatabase.Refresh();