branchProtectionRules queries always return null

I’m trying a simple query to try to get Github’s ID for a branch protection rule in our repo, but have found that the branchProtectionRules method always returns null data

query { 
  repository(owner:"slackhq",name:"keeper") {
    branchProtectionRules(first:10) {
      nodes {
        pattern
      }
    }
  }
}

I’m an admin of this repo and am just testing in the explorer, but this always returns the following json. Am I missing something basic about this query or is the method broken?

{
  "data": {
    "repository": {
      "branchProtectionRules": {
        "nodes": [
          null
        ]
      }
    }
  }
}

Nevermind. While being an admin, it appears that this is not readable by admins designated as “outside contributors” of the org the repo is in