Open Messaging API rejecting structured quick reply payload in Terraform-managed bot

We are deploying a bot via the CX-as-Code provider and need to send structured quick replies through the Open Messaging API. The Terraform state is clean, but the runtime call to POST /api/v2/conversations/messages returns a 400 Bad Request. It seems the message structure does not match the expected schema for structured content.

Here is the JSON payload we are sending in the request body. Can anyone spot why the platform rejects this specific format? We have verified the OAuth token is valid and has the required scopes.

{
“to”: { “id”: “user-123” },
“text”: “Select an option”,
“quickReply”: { “options”: [{ “label”: “Yes”, “value”: “y” }] }
}