Subquery element null when using a fragment

Client SDKs
1

We have a query like this that works as expected:

query GetItems($getItemsInput: GetItemsInput!) {
  getItems(getItemsInput: $getItemsInput) {
    uuid
    user {
      firstName
      lastName
    }
  }
}

But when I use a fragment with the same inputs, the “user” comes back null (uuid is there both ways)

query GetItems($getItemsInput: GetItemsInput!) {
  getItems(getItemsInput: $getItemsInput) {
    ...ItemsRow
  }
}

fragment ItemsRow on Item {
  uuid
  user {
    firstName
    lastName
  }  
}

Any ideas on why and/or where we should look to figure this out? This is using the Playground as the client.

2

Is Item here the actual type or an interface? In the case of an interface, the playground might not be aware of a parent-child relationship between the Item interface and the actual type.

3

It is a type. And it also happens when using the React Apollo client

4

Turns out it was the result of an optimization we were doing on the backend. Worked it out.