Excessive outgoing traffic usage from database instance?

I’ve deployed a “hello world” Phoenix app. If I view my organisations usage page, I can see almost 800mb of outgoing traffic for the database instance. This seems… excessive. This is not an app that does anything or has been published anywhere. Why is the the usage so high?

The metrics don’t seem to support the outgoing data:

This is essentially an empty Postgres database. Perhaps one table to track the migrations that have been run.

Ah, I can see this has been answered in Outbound data transfer for Postgres - #8 by kurt

That 12KB/s sustained adds up! It’s not actually that much traffic, but it’s definitely more than 0.