So here's what i'm doing.
When i use a predefined list of elements, this is the presentation. And if i change Appliance, the Group Name doesn't change which is as you described.
when i use a data binding with the exact same OGNL action being called, this is what i get
So i know that the action is returning an array of strings because that's showing up properly in the first image.
I'm not sure what i'm missing.