Understood. Obviously there is a conflict. Something else appear to have the same name at the same level.
Make a note somewhere (model annotation) and make the - &A - and see what it returns. If it returns a value or something else recognizable, now you know where to look. If it comes back with an error, we'll move onto the next step.
I'm still wondering if "A" was accidentally defined but not used anywhere. Which means it can be deleted... but you have to find it 1st 