Never had an issue before. I saw a post about it that said a fix was coming 10 days ago but nothing after that. I just started seeing it within the last 5 hours. the error is below.
Error failed loading app config from: /github/workspace/fly.toml: json: cannot unmarshal string into Go struct field Experimental.experimental.cmd of type string
Hi, we released flyctl v0.0.459 about 7 hours ago. I suspect that caused this issue. I’m investigating now. We’ll rollback shortly if we don’t find a fix.
I’m guessing you don’t deploy often 
There is an issue with deployment at least once a month, it’s honestly reached the point of absurdity. Fly.io’s core infrastructure is brilliant, flyctl, the GHA and their docker image integration cause nothing but headaches though.
A new release is coming shortly with a fix for this. Meanwhile, I’ll point out that for critical deployments, it might be worth pinning to a flyctl version documented here:
- uses: superfly/flyctl-actions/setup-flyctl@master
with:
version: 0.0.458
We have fixed this issue in v0.0.462, which was released a few minutes ago.