I think you are facing the same problem as I have already answered in this thread.
The rule with @cascade(predicate) is that the predicate needs to be in the query at the same level @cascade is. So, @cascade(carName) at a level where carName isn’t a predicate won’t have any effect, while @cascade(cars) works because the predicate cars exists at that level in the query.
Sorry for the confusion you faced. We have noted that we need to update our docs about the finer details of how @cascade works.
Thanks