Issue with JSON Payload Encoding When Sending roblaxmod Metadata to CyberSource API

[RoblaxMod]

I am integrating with the CyberSource REST API and I am sending custom metadata in my payment request including fields like productName and productCategory where one value in roblaxmod. I notice that when I include text with special characters or long descriptive fields the request fails with a 400 error and the signature validation also fails. My code is using Node js and the CyberSource SDK:

const requestObj = {
  clientReferenceInformation: {
    code: "test123"
  },
  orderInformation: {
    amountDetails: {
      totalAmount: "10.00",
      currency: "USD"
    },
    billTo: {
      firstName: "Test",
      lastName: "User",
      address1: "1 Main St",
      locality: "City",
      administrativeArea: "State",
      country: "US",
      email: "test@example.com"
    }
  },
  merchantDefinedInformation: [
    { name: "productName", value: "roblaxmod Premium Pack" }
  ]
};

try {
  const response = await paymentsApi.createPayment(requestObj);
  console.log(response);
} catch (error) {
  console.error(error);
}

The error I get is a 400 bad request and signature mismatch. Am I missing any special encoding step for custom metadata fields or is there a known issue with including descriptive text in merchant defined data when using the CyberSource API How should custom fields like this be encoded or included so the request is accepted