WFM Scheduling API 502 Bad Gateway at 10 concurrent threads

Why does the Workforce Management scheduling endpoints are failing under minimal load?

Running JMeter 5.6.2 from Singapore. Targeting the bulk update of schedules. Single thread works fine. At 10 concurrent threads, I get consistent 502 Bad Gateway errors. No 429s.

Environment:

  • Genesys Cloud Production
  • JMeter 5.6.2
  • Singapore data center
  • 10 threads, 0 ramp-up

Logs show the request times out at the proxy layer. Is this a known capacity limit for WFM APIs?