Hi v-yuta-msft , thanks for reply. Please find my comments below :
1. The data changes everyday at 6:15 AM EET in data source with new data, and the start time of schedule refresh in Power BI, 6:30 AM EET.
2. After the data refresh, the new data is reflected in Power BI service, but NOT in the snapshot of subscribed mail. As I said, it takes around 15 mins to reflect the new data in Power BI service, so technically the data is reflected at 6:45 AM EET but the snapshot is taken within 3 min of schedule refresh at 6:33 AM EET.