Ember Data - Nested embedded records return null

We have a scenario when an embedded record of an embedded record returns null.

The relationship chain looks like this: userProfile --belongsTo--> organisation --hasOne (i.e. belongsTo)--> jurisdiction.

However, when fetching all userProfile records, the jurisdiction remains unpopulated.

So far, the respective serializers and models look like this:

UserProfile

Model

organisation: belongsTo('organisation', { async: false }),

Serializer

 attrs: {
    'organisation': { embedded: 'always' },
    ...
  },

Organisation

Model

userProfile: hasMany('userProfile', { async: false }),
jurisdiction: belongsTo('jurisdiction', { async: false }),

Serializer

  attrs: {
    ...
    'jurisdiction': { embedded: 'always' },
  },

Jurisdiction

Model

organisation: belongsTo('organisation', { async: false }),

Serializer

  attrs: {
    ...
    area: { key: 'jurisdictionArea' },
    name: { key: 'jurisdictionName' },
  },

I believe the issue might be that this part of the API doesn't appear to conform to the the JSON API spec, as an example userProfile response might look like:

...
organisation: {
   jurisdictionArea: "TAU"
   jurisdictionId: "82cfda0b-3180-41cf-b0fa-b1193655bc0b"
   organisationId: "960d4ec2-bc90-11e8-a355-529269fb1459"
}

I think this might be able to be resolved via the normalizeResponse or serializeBelongsTo methods in the organisation serializer, however, so far my attempts have not been successful. Any advice on how to resolve this would be much appeaciated.