Realm GraphQL not returning all objects

I’ve come across a problem that I can’t resolve by myself because is something that it’s out of my current knowledge.

Context:
The goal is to make a grocery list app

Problem explanation:
I’ve got a collection where every object has a objectId array (where I push all the groceries I want to shop) that references objects from other collection (groceries item). The problem comes when I push the same item more than once, because GraphQL seems like is returning me a distinct objectId array (i.e I got only one item with the same _id).

Is there something that I’ve been missing?