Why do DPS queries occasionally run slow.

Question

I have a function app that queries the DPS to determine what hub a device is attached to so it can send a device to cloud message. Normally these run quickly, but occasionally they are sow. I have no exceptions or errors:
How can I diagnose the cause of these and resolve.
This was not helpful: https://learn.microsoft.com/en-us/azure/iot-dps/how-to-troubleshoot-dps#troubleshooting-with-azure-iot-hub-device-provisioning-service