Hm… The health checks use the 172.16.* private address range, or at least they have in the past. Could you log more of the request header (e.g., the user-agent)?
In general, internal traffic (apart from Flycast) won’t keep Machines awake, though. The Grafana metrics (“app concurrency”) should tell you what the Fly Proxy thinks your external traffic really is…
Also, it’s a good idea to post your entire fly.toml in this situation. (Feel free to * out any names that you consider sensitive, but show the full structure.)
Hope this helps a little!