Statistics API /api/v2/analytics/queues/realtime returning stale agent counts

Hitting the Statistics API endpoint GET /api/v2/analytics/queues/realtime?queues.id=12345 from my Kotlin Android service. The response comes back with a 200 OK, but the agentsAvailable count is stuck at 5 even though I know agents are logging out in real-time.

{
 "entities": [
 {
 "agentsAvailable": 5,
 "waiting": 0,
 "id": "12345"
 }
 ]
}

The lastUpdated timestamp in the header is 30 seconds old. Is there a query parameter to force a cache bypass or a stricter interval? I’ve tried adding since= but it just throws a 400.