Some times OCI usage api currency getting empty

I am facing an issue with the Usage API currency field. Sometimes, the currency value returns as None. Please let me know if any changes are required—I will make them accordingly.
@adizohar

{
  "ad": null,
  "attributed_cost": "0",
  "attributed_usage": "0",
  "compartment_id": null,
  "compartment_name": "Infolob",
  "compartment_path": null,
  "computed_amount": 0.93,
  "computed_quantity": 0.0,
  "currency": " ",
  "discount": null,
  "is_forecast": false,
  "list_rate": null,
  "overage": null,
  "overages_flag": null,
  "platform": null,
  "region": null,
  "resource_id": "ocid1.bootvolume.oc1.ap-hyderabad-1.abuhsljrv776x6swqtdpzskszcrs6dni6i4pmm755sp4pylg34twke2h2rqa",
  "resource_name": null,
  "service": "Block Storage",
  "shape": null,
  "sku_name": null,
  "sku_part_number": null,
  "subscription_id": null,
  "tags": [
    {
      "key": null,
      "namespace": null,
      "value": null
    }
  ],
  "tenant_id": null,
  "tenant_name": null,
  "time_usage_ended": "2025-06-0500:00:00+00:00",
  "time_usage_started": "2025-06-04T00:00:00+00:00",
  "unit": null,
  "unit_price": null,
  "weight": null
}
--------
{
  "ad": null,
  "attributed_cost": "0",
  "attributed_usage": "0",
  "compartment_id": null,
  "compartment_name": "Infolob",
  "compartment_path": null,
  "computed_amount": null,
  "computed_quantity": 0.0,
  "currency": " ",
  "discount": null,
  "is_forecast": false,
  "list_rate": null,
  "overage": null,
  "overages_flag": null,
  "platform": null,
  "region": null,
  "resource_id": "ocid1.bootvolume.oc1.ap-hyderabad-1.abuhsljrv776x6swqtdpzskszcrs6dni6i4pmm755sp4pylg34twke2h2rqa",
  "resource_name": null,
  "service": "Block Storage",
  "shape": null,
  "sku_name": null,
  "sku_part_number": null,
  "subscription_id": null,
  "tags": [
    {
      "key": null,
      "namespace": null,
      "value": null
    }
  ],
  "tenant_id": null,
  "tenant_name": null,
  "time_usage_ended": "2025-06-04T00:00:00+00:00",
  "time_usage_started": "2025-06-03T00:00:00+00:00",
  "unit": null,
  "unit_price": null,
  "weight": null
}

No repository file, test, or entry point is named. Start by reproducing the OCI Usage API response and tracing whether the blank currency originates in the service response or SDK handling; done means identifying the source and the expected currency behavior.