apollo doesn't return values nor error when [Episode]! type has null value

array_with_null_value_type.rb

module Types

  Level1Type = GraphQL::ObjectType.define do
    name "Level1Type"
    field :name, types.String
  end

  ArrayWithNullValueType = GraphQL::ObjectType.define do
    name "ArrayWithNullValueType"
    field :level1s, !types[Level1Type]
  end
end

GraphiQL.png

query_type.rb

module Types
  QueryType = GraphQL::ObjectType.define do
    name "Query"

    field :ArrayWithNullValue do
      type !ArrayWithNullValueType

      resolve ->(obj, args, ctx) {
        level1s = [
          nil,
          OpenStruct.new(name: "some name1"),
          OpenStruct.new(name: "some name2")
        ]
        OpenStruct.new(level1s: level1s)
      }
    end
  end
end