Azure IoT Central is exporting data from difference sources. The 'Measurement' source periodically streaming a device telemetry and non-telemetry data in opposite to the 'Device' source, which is based on the eventing changes on the device twin properties (such as cloud, settings, properties).
In other words, these sources are independent and there is no guarantee that they are happen in either the same time or close to each other.
However, there is a way to minimize this traffic for emails using an Azure Stream Analytics (ASA) job with some aggregation query and windowing functions.
The ASA job can forward an output to the HttpTrigger Function for sending an emails.