OneSignal change history: Intermittent errors on /api/v1/notifications api

OneSignal reported major intermittent errors creating notifications through /api/v1/notifications, affecting some customers from 2026-09-18 00:48 UTC until resolution at 2026-09-18 01:23 UTC (34 min). Heavy load on a notification service caused the errors; OneSignal scaled up resources and confirmed the endpoint was stable for all customers.