{
  "ds-improved-ajax": null,
  "ds-pushpayload-return": null,
  "ds-extended-errors": null,
  "ds-overhaul-references": null,
  "ds-payload-type-hooks": null,
  "ds-check-should-serialize-relationships": null,
  "ds-rollback-attribute": null,
  "ds-serialize-id": null,
  "ds-deprecate-store-serialize": true
}

{
  "ds-improved-ajax": null,
  "ds-pushpayload-return": null,
  "ds-extended-errors": null,
  "ds-overhaul-references": null,
  "ds-payload-type-hooks": null,
  "ds-check-should-serialize-relationships": true,
  "ds-rollback-attribute": null,
  "ds-serialize-id": null,
  "ds-deprecate-store-serialize": true
}

Enable the ds-check-should-serialize-relationships feature flag
Enable the ds-check-should-serialize-relationships feature flag