Binary cache not getting hit and GHC keeps building?

[ovitus]

• 86_64-linux
• GHC 9.4.8
• Haskell.nix commit 12913ad

My configuration flake contains:
nix.settings.substituters = [ "https://cache.iog.io" ];
nix.settings.trusted-public-keys = [ "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ=" ];

The Haskell flake:
nixConfig = {
extra-substituters = ["https://cache.iog.io"];
extra-trusted-public-keys = ["hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="];
allow-import-from-derivation = "true";
};
}

And yet when I run "nix develop" it goes through the lengthy process of building ghc-9.4.8 from scratch. The binary cache doesn't seem to be getting hit.

[chreekat]

I just tried following https://input-output-hk.github.io/haskell.nix/tutorials/getting-started-flakes.html#using-flake-init-and-nix and ran into the same problem.

$ nix build .#hello:exe:hello
trace: WARNING: 9.2.6 is out of date, consider using upgrading to 9.2.8.
trace: WARNING: 9.2.6 is out of date, consider using upgrading to 9.2.8.
trace: WARNING: 9.2.6 is out of date, consider using upgrading to 9.2.8.
trace: WARNING: 9.2.6 is out of date, consider using upgrading to 9.2.8.
trace: WARNING: 9.2.6 is out of date, consider using upgrading to 9.2.8.
[1/3/6 built, 0.0 MiB DL] building ghc-9.2.6 (configurePhase): checking for float... yes

Also, why is it picking 9.2.6? (Edit: I guess it could be that it wants to bootstrap the whole chain, and 9.2.6 is the first one missing in the cache.)