Predictive Routing API returning 400 on bulk wrap-up

Hey everyone, I’ve run into a really strange issue with POST /api/v2/predictiverouting/outboundcampaigns/{id}/wrapup. JMeter 5.6.2 from Singapore is hitting this endpoint and getting 400 Bad Request. Payload looks correct in Postman but fails under load.

{
 "status": "COMPLETED",
 "wrapupCode": "SURVEY_SENT",
 "callResult": "CONTACTED"
}

Any ideas why this fails specifically during high concurrency?