Just following up it seems to have been Cloudflare caching. I think it cached it while the site was down. I had to purge the Cloudflare cache to get it serving the new assets.
My deployed site keeps returning 404 for static css assets
/assets/index-74b5208c.css ← return 404
adding an extra forward slash to the path shows that the file is there.
//assets/index-74b5208c.css
This is only on the app that is on my domain the issue does not occur app.fly.dev domain.
I am not sure if my app is in a weird state as I originally deployed it during an outage. Any help would be greatly appreciated.