Some non-nullable fields are returning null

[nakib103]

Description

Some non-nullable fields defined in the schema are returning null. They are -
length
assembly
sequence
metadata

from Region under Slice -

ensembl-hypsipyle/common/schemas/slice.graphql

Lines 20 to 29 in 1e5e09c

	type Region {
	# A large contiguous block of assembled sequence, such as a whole chromosome.
	name: String!
	length: Int!
	code: RegionCode!
	topology: RegionTopology!
	assembly: Assembly!
	sequence: Sequence!
	metadata: RegionMetadata!
	}

Example query

query variant_example {
  variant(
    by_id: {genome_id: "a7335667-93e7-11ec-a39d-005056b38ce3", variant_id: "2:10171:rs1572047411"}
  ) {
    name
    slice {
      default
      region {
        name
        code
        topology
        assembly{
          accession_id
        }
        length
        sequence {
          alphabet {
            accession_id
          }
        }
        metadata{
          ontology_terms {
            accession_id
          }
        }
      }
    }
  }
}