This is a common issue - when you write rows into Excel, there is a delay due to caching before the data is commited to the document. Since the flow runs the next action right after the previous one, the data hasn't been commited to the worksheet yet.
You have two options
1. Introduce a delay action in your flow, and wait 30 seconds before you send out the email.
2. Write an office script to refresh all data in all the tables in the worksheet, and trigger the office script using the Flow before you move onto the next step.
Hope this helps