The _counter variable does not increment because the code uses recordcount outside the context of a query-based loop, so it's always 1.

The following line in coldbox.system.web.Renderer

Should instead be:

That said, I actually think we should take this opportunity (since no one has apparently every used this feature) and return each collection pivot as a struct representing that query row. collection.column is much better than collection.column[ _counter ]. Lucee has native for/in looping that returns query rows as a struct, but ACF would require a bit of looping to build it I think.