502 Bad Gateway - Remix 2.4.1, Vite, and Fly.io

[hazy sluice]

I just upgrade my app to Remix 2.4.1 and I'm using Vite. I've started to see 502 errors when I submit a form and then redirect. It doesn't happen every time but happens a decent amount. Is this a remix error or a fly.io error? I'm not sure where to look to debug. The only log I see on the backend is this

instance refused connection. is your app listening on 0.0.0.0:3000? make sure it is not only listening on 127.0.0.1 (hint: look at your startup logs, servers often print the address they are listening on)

[shut beacon]

are you using express server?

I wonder if fly is shutting the instance down because healthcheck

If you have the fly.toml at hand to take a quick look

[hazy sluice]

I think this is a bug in 2.4.1.. If I switch to 2.3 it goes away. There was a weird error that was also in the logs so I think this log is a red herring. Thanks for the response thoguh