Document that nested @each does not work

source/guides/object-model/computed-properties-and-aggregate-data.md

@@ -53,3 +53,6 @@ todos.pushObject(todo);
 App.todosController.get('remaining');
 // 1
 ```
+
+Note that `@each` only works one level deep. You cannot use nested forms like
+`[email protected]` or `[email protected][email protected]`.