CXone Studio handover to Cognigy fails with 500 on session update

Running into a hard wall when trying to pass a session from a CXone Studio script to a NICE Cognigy voicebot. The Studio script hits the external API endpoint to initialize the bot, but the subsequent session handover fails immediately.

The error is a generic 500 Internal Server Error from the CXone runtime, but the logs show the Cognigy response is technically a 200 OK with the session ID. It looks like Studio isn’t parsing the payload correctly before attempting the handover. Here’s the ASSIGN snippet I’m using to set the context:

ASSIGN: handoverPayload = {
 "sessionId": "{{botSessionId}}",
 "interactionId": "{{interactionId}}",
 "metadata": {
 "source": "studio_handover",
 "timestamp": "{{now}}"
 }
}

The API call to Cognigy succeeds, but the Studio flow crashes right after. Is there a specific format requirement for the handover payload that I’m missing? Or is this a known issue with the latest Studio runtime update?