Scripting API 400 Error on BYOC with JSON payload

Why does the Genesys Cloud Scripting API returns a 400 Bad Request when provisioning a script via Terraform on AU-1 BYOC? Provider v1.22.0. The flow seems valid but the API rejects the content structure.

{
 "name": "Test Script",
 "content": "<script><step type='playPrompt' promptId='123'/></script>"
}