ServiceNow Data Action failing on nested JSON payload

Quick question about Data Actions mapping complex nested JSON from Genesys Cloud to ServiceNow REST APIs.

Background

Using a custom Data Action to push engagement metadata to ServiceNow via POST. The payload contains nested objects for interaction history.

Issue

The Action logs a 400 Bad Request. ServiceNow returns JSON_PARSING_ERROR: Unexpected token. The payload looks valid in the preview, but the execution fails consistently.

Troubleshooting

  • Verified the payload against ServiceNow’s API docs. Standard flat payloads work fine.
  • Checked for unescaped characters in the JSON string. None found.
  • Tested the same payload directly via Postman to ServiceNow. It succeeds.

Is there a known limitation with nested JSON serialization in Data Actions?