Why won't my resource use another resource as export?

Question

Hi, so I have a resource which passes dialogue to the UI and it works.

In order to have dialogue be flexible, I wanted to keep a different file for each Item so I can change the dialogue and swap files as needed(so interactions change when events happens, different story branch...etc)

However, I tried using the subresource as value for the couch dialogue and it never works. It never considers it and returns this error:

Invalid get index "couch" {on base: 'nil'}.

extends Resource
class_name Interactable

export var dialog : Resource

export var items : Array = [
{
    "name": "CouchLivingRoom",
    "dialogue": dialog.couch,    - # Right here
},
{
    "name": "RefrigeratorKitchen",
    "dialogue": "This is a fridge",
}
]

I thought this would work out of the box, but I assume there's some problem with loading resources at runtime? does loading resources to another resource even work?

Please let me know how I can fix this or if there's a better way of doing this.