fulfillmentOutbound / createFulfillmentOrder / destinationAddress does not accept DC as a valid stateOrRegion

[leesilverman]

I'm able to place orders for all other US States. When I try to specify DC in the stateOrRegion parameter I get this error. However, when I use Postman to call SP-API with the exact same body, it goes through just fine.

{
"code": "InvalidInput",
"message": "Request has invalid parameter: {Address.StateOrRegion=DC}",
"details": "",
"type": "error"
}