I’m not sure if your Github Action has docker available locally, but until someone from Fly responds one thing you could quickly try is swap the deploy command to either use/not-use the remote builder and see which helps.
Like … swap from fly deploy to fly deploy --remote-only (or vice versa).
The Fly CLI defaults to using a local docker if it’s available and that can be better than using a remote builder. Depending on the networking, setup etc. It’s certainly worth a try swapping to see which works best for you.
Else this may be a regression, though unlikely. That problem used to happen to me a lot (a random timeout caused by a peer delay). The temporary fix back then was to persist the config.yml file that the Fly CLI makes. That file contains a load of networking stuff and presumably results in it being re-ued. Deploying from local, of course that file is always there. But from CI it’s generally not persisted. Ii say unlikely because Fly have fixed that issue. So persisting that config.yml shouldn’t be needed and deploys should take seconds. But if you want to check that out in case it’s that in the meantime too, it’s this big long thread: