CXone Reporting API aggregation for 30-min intervals returning empty

Trying to pull agent utilization metrics (tHandle, tAcw, tHold) from CXone Reporting API broken down by 30-minute intervals. The query runs without error but returns an empty dataset even though we have active agents.

$filter=timestamp ge 2023-10-26T08:00:00Z and timestamp lt 2023-10-26T09:00:00Z&$interval=PT30M
  • Environment: CXone Production, US/Pacific
  • Endpoint: /api/v2/analytics/agents/summary
  • Tried switching $interval to PT1H which works fine
  • Verified agents were logged in during that window

Anyone know if PT30M is supported for this specific endpoint?